# eFuse Manager

[中文]

## Introduction

eFuse (Electronic Fuses) are microscopic one-time programmable fuses that can be "burned" (i.e., programmed) to store data into the ESP32-H4. eFuse bits are organized into different data fields, and these data fields could be used for system parameters (i.e., data parameters used by ESP-IDF of ESP32-H4) or user defined parameters.

The eFuse Manager component is a collection of tools and APIs that assist with defining, burning, accessing eFuses parameters. The notable tools and APIs include:

- A table format used to define eFuse data fields in CSV file.

- `efuse_table_gen.py` tool to generate C structure representation of eFuse data fields specified by the CSV file.

- Collection of C API to read/write eFuse data fields.

## eFuse Manager vs `idf.py`

`idf.py` provides a subset of the functionality of the eFuse Manager via the `idf.py efuse-<subcommand>` commands. In this documentation, mostly `idf.py` based commands will be used, although you can still see some `espefuse` based commands for advanced or rare cases. To see all available commands, run `idf.py --help` and search for those prefixed with `efuse-`.

## Hardware Description

The ESP32-H4 has a number of eFuses which can store system and user parameters. Each eFuse is a one-bit field which can be programmed to 1 after which it cannot be reverted back to 0. The eFuse bits are grouped into blocks of 256 bits, where each block is further divided into 8 32-bit registers. Some blocks are reserved for system parameters while the remaining blocks can be used for user parameters.

For more details, see ESP32-H4 Technical Reference Manual > eFuse Controller (eFuse) [PDF].

ESP32-H4 has 11 eFuse blocks each containing 256 bits (not all bits can be used for user parameters):

- EFUSE_BLK0 is used entirely for system parameters

- EFUSE_BLK1 is used entirely for system parameters

- EFUSE_BLK2 is used entirely for system parameters

- EFUSE_BLK3 (also named EFUSE_BLK_USER_DATA) can be used for user parameters

- EFUSE_BLK4 to EFUSE_BLK8 (also named EFUSE_BLK_KEY0 to EFUSE_BLK_KEY4) can be used to store keys for Secure Boot or Flash Encryption. If both features are unused, these blocks can be used for user parameters.

- EFUSE_BLK9 (also named EFUSE_BLK_KEY5) can be used for any purpose except for Flash Encryption or ECDSA (due to a HW errata);

- EFUSE_BLK10 (also named EFUSE_BLK_SYS_DATA_PART2) is reserved for system parameters.

## Defining eFuse Fields

eFuse fields are defined as a table of records in a CSV file according to a specific format. This record format provides the ability to form eFuse fields of any length and from any number of individual bits.

Moreover, the record format allows structured definition of eFuse fields consisting of sub-fields, meaning that a parent eFuse field may consist of multiple child eFuse fields occupying the same eFuse bits.

### Record Format

In simple cases, each record occupies a single row in the table. Each record contains the following values (i.e., columns):

    # field_name, efuse_block(EFUSE_BLK0..EFUSE_BLK10), bit_start(0..255), bit_count(1..256), comment

- `field_name`

  > - Name of the eFuse field.

  > - The prefix `ESP_EFUSE_` is automatically added to the name, and this name will be used when referring to the field in C code.

  > - `field_name` unique across all eFuse fields.

  > - If this value is left empty, then this record is combined with the previous record. This allows you define an eFuse field with arbitrary bit ordering (see `MAC_FACTORY` field in the common table).

  > - Using `.` will define a child eFuse field. See Structured eFuse Fields for more details.

- `efuse_block`

  > - The eFuse field's block number. E.g., EFUSE_BLK0 to EFUSE_BLK10.

  > - This determines which block the eFuse field is placed.

- `bit_start`

  > - Bit offset (0 to 255) of the eFuse within the block.

  > - `bit_start` is optional and can be omitted.

  >   > - In this case, it is set to `bit_start + bit_count` from the previous record, given that the previous record is in the same eFuse block.

  >   > - If the previous record is in a different eFuse block, an error will be generated.

- `bit_count`

  > - The size of the eFuse field in bits (1 to N).

  > - `bit_count` cannot be omitted.

  > - If set to `MAX_BLK_LEN` the eFuse field's size will be the maximum allowable eFuse field size in the block.

- `comment`

  > - Comment describing the eFuse field.

  > - The comment is copied verbatim into the C header file.

If an eFuse field requires non-sequential bit ordering, then the eFuse field will span multiple records (i.e., multiple rows). The first record's `field_name` should specify the eFuse field's name, and the following records should leave `field_name` blank to indicate that they belong to the same eFuse field.

The following example demonstrates the records to specify the non-sequential eFuse field `MAC_FACTORY` followed by a regular eFuse field `MAC_FACTORY_CRC`:

    # Factory MAC address #
    #######################
    MAC_FACTORY,            EFUSE_BLK0,    72,    8,    Factory MAC addr [0]
    ,                       EFUSE_BLK0,    64,    8,    Factory MAC addr [1]
    ,                       EFUSE_BLK0,    56,    8,    Factory MAC addr [2]
    ,                       EFUSE_BLK0,    48,    8,    Factory MAC addr [3]
    ,                       EFUSE_BLK0,    40,    8,    Factory MAC addr [4]
    ,                       EFUSE_BLK0,    32,    8,    Factory MAC addr [5]
    MAC_FACTORY_CRC,        EFUSE_BLK0,    80,    8,    CRC8 for factory MAC address

This eFuse fields will be made available in C code as `ESP_EFUSE_MAC_FACTORY` and `ESP_EFUSE_MAC_FACTORY_CRC`.

## Structured eFuse Fields

Typically, an eFuse field represents a particular parameter. However, in some cases where an eFuse field consists of multiple sub-fields, it may be useful to have isolated access to those sub-fields. For example, if an eFuse field contained a floating point parameter, it may be useful to be access the sign, exponent, and mantissa fields of the floating as separate eFuse fields.

Therefore, it is possible for records to define eFuse fields in a structured manner using the `.` operator in `field_name`. For example, `XX.YY.ZZ` defines a eFuse field `ZZ` that is a child of eFuse field `YY` which in turn is a child field of eFuse field `XX`.

The following records demonstrate the definition of eFuse fields in a structured manner:

    WR_DIS,                           EFUSE_BLK0,   0,    32,     Write protection
    WR_DIS.RD_DIS,                    EFUSE_BLK0,   0,    1,      Write protection for RD_DIS
    WR_DIS.FIELD_1,                   EFUSE_BLK0,   1,    1,      Write protection for FIELD_1
    WR_DIS.FIELD_2,                   EFUSE_BLK0,   2,    4,      Write protection for FIELD_2 (includes B1 and B2)
    WR_DIS.FIELD_2.B1,                EFUSE_BLK0,   2,    2,      Write protection for FIELD_2.B1
    WR_DIS.FIELD_2.B2,                EFUSE_BLK0,   4,    2,      Write protection for FIELD_2.B2
    WR_DIS.FIELD_3,                   EFUSE_BLK0,   5,    1,      Write protection for FIELD_3
    WR_DIS.FIELD_3.ALIAS,             EFUSE_BLK0,   5,    1,      Write protection for FIELD_3 (just a alias for WR_DIS.FIELD_3)
    WR_DIS.FIELD_4,                   EFUSE_BLK0,   7,    1,      Write protection for FIELD_4

Some things to note regarding the example above:

- The `WR_DIS` record defines the parent eFuse field. All the other records are child fields of `WR_DIS` due to their `WR_DIS.` prefix.

- The child fields must utilize the same bits as their parent field. Take note of `bit_start` and `bit_count` of the child and parent fields:

  > - The bits of the child fields are always in the range of their parent field. For example, `WR_DIS.RD_DIS` and `WR_DIS.RD_DIS` occupy the first and second bit of `WR_DIS`.

  > - Child fields cannot use overlapping bits (except for when aliasing).

- It is possible to create aliases as a child field. For example, `WR_DIS.FIELD_3.ALIAS` is a child field and alias of `WR_DIS.FIELD_3` as they both occupy the same bits.

All eFuse Fields are eventually converted to C structures via the `efuse_table_gen.py` tool. The C structure for each eFuse field will derive their identifier from the `field_name` of the eFuse field's record, where all `.` are replaced with `_`. For example, the C symbols for `WR_DIS.RD_DIS` and `WR_DIS.FIELD_2.B1` will be `ESP_EFUSE_WR_DIS_RD_DIS` and `ESP_EFUSE_WR_DIS_FIELD_2_B1` respectively.

The `efuse_table_gen.py` tool also checks that the fields do not overlap each other and must be within the range of a field. If there is a violation, then the following error is generated:

    Field at USER_DATA, EFUSE_BLK3, 0, 256 intersected with SERIAL_NUMBER, EFUSE_BLK3, 0, 32

In this case, the error can be resolved by making `SERIAL_NUMBER` a child field of `USER_DATA` via `USER_DATA.SERIAL_NUMBER`.

    Field at FIELD, EFUSE_BLK3, 0, 50 out of range FIELD.MAJOR_NUMBER, EFUSE_BLK3, 60, 32

In this case, the error can be resolved by changing `bit_start` for `FIELD.MAJOR_NUMBER` from `60` to `0` so that `MAJOR_NUMBER` overlaps with `FIELD`.

## `efuse_table_gen.py` Tool

The `efuse_table_gen.py` tool is designed to generate C source files containing C structures (of type `esp_efuse_desc_t`) representing the eFuse fields defined in CSV files. Moreover, the tool also runs some checks on the provided CSV files before generation to ensure that:

- the names of the eFuse fields are unique

- the eFuse fields do not use overlapping bits

As mentioned previously, eFuse fields can be used to hold either system parameters or user parameters. Given that system parameter eFuse fields are inherently required by ESP-IDF and ESP32-H4, those eFuse fields are defined in a common CSV file (`esp_efuse_table.csv`) and distributed as part of ESP-IDF. For user parameter eFuse fields, users should define those fields in a custom CSV file (e.g., `esp_efuse_custom_table.csv`).

To generate C source files using the common CSV file, use the `idf.py efuse-common-table` or the following:

    cd $IDF_PATH/components/efuse/
    ./efuse_table_gen.py --idf_target esp32h4 esp32h4/esp_efuse_table.csv

The following C source/header files will be generated by the tool in `$IDF_PATH/components/efuse/esp32h4`:

- `esp_efuse_table.c` file containing the C structures of the system parameter eFuse fields

- `esp_efuse_table.h` file in the `include` folder. This header can be included by the application to use those C structures.

To generate C source files using a custom CSV file, use the command `idf.py efuse-custom-table` or the following:

    cd $IDF_PATH/components/efuse/
    ./efuse_table_gen.py --idf_target esp32h4 esp32h4/esp_efuse_table.csv PROJECT_PATH/main/esp_efuse_custom_table.csv

The following C source/header files will be generated by the tool in `PROJECT_PATH/main`:

- `esp_efuse_custom_table.c` file containing the C structures of the user parameter eFuse fields

- `esp_efuse_custom_table.h` file in the `include` folder. This header can be included by the application to use those C structures.

To use the generated fields, you need to include two files:

    #include "esp_efuse.h"
    #include "esp_efuse_table.h" // or "esp_efuse_custom_table.h"

## Supported Coding Schemes

Various coding schemes are supported by eFuses which can protect eFuses against data corruption by detecting and/or correcting for errors.

ESP32-H4 does not support selection of coding schemes. The following coding schemes are automatically applied to various eFuse blocks:

- `None`: Applied to EFUSE_BLK0

- `RS`: Applied to EFUSE_BLK1 - EFUSE_BLK10

### `None` Coding Scheme

The `None` coding scheme is automatically applied to EFUSE_BLK0. This scheme does not involve any encoding, but simply maintains four backups of EFUSE_BLK0 in hardware, meaning each bit is stored four times. As a result, EFUSE_BLK0 can be written many times.

This scheme is automatically applied by the hardware and is not visible to software.

### `RS` Coding Scheme

The `RS` coding scheme uses Reed-Solomon encoding and is automatically applied to EFUSE_BLK1 to EFUSE_BLK10. The coding scheme supports up to 6 bytes of automatic error correction.

Software encodes the 32-byte EFUSE_BLKx using `RS(44, 32)` to generate a 12-byte check-symbols, and then burn the EFUSE_BLKx and the check-symbols into eFuse at the same time.

The eFuse Controller automatically decodes the `RS` encoding and applies error correction when reading back the eFuse block. Because the `RS` check-symbols are generated across the entire 256-bit eFuse block, each block can only be written to one time. As a result of the check-symbols, Batch Writing Mode must be used.

### Batch Writing Mode

When writing to eFuse fields at run time, it may be necessary to use the Batch Writing Mode depending on the coding scheme used for eFuse block. Batch writing mode can be used as follows:

1. Enable batch writing mode by calling `esp_efuse_batch_write_begin()`

2. Write to the eFuse fields as usual using various `esp_efuse_write_...` functions.

3. Once all writes are complete, call `esp_efuse_batch_write_commit()` which burns prepared data to the eFuse blocks.

Warning

If there is already pre-written data in the eFuse block using the `Reed-Solomon` encoding scheme, then it is not possible to write anything extra (even if the required bits are empty) without breaking the previous data's checksums/check-symbols.

The checksums/check-symbols will be overwritten with new checksums/check-symbols and be completely destroyed (however, the payload eFuses are not damaged).

If you happen to find pre-written data in CUSTOM_MAC, SPI_PAD_CONFIG_HD, SPI_PAD_CONFIG_CS, etc., please contact Espressif to obtain the required pre-burnt eFuses.

FOR TESTING ONLY (NOT RECOMMENDED): You can ignore or suppress errors that violate encoding scheme data in order to burn the necessary bits in the eFuse block.

## eFuse API

Access to the fields is via a pointer to the description structure. API functions have some basic operation:

- `esp_efuse_read_field_blob()` - returns an array of read eFuse bits.

- `esp_efuse_read_field_cnt()` - returns the number of bits programmed as "1".

- `esp_efuse_write_field_blob()` - writes an array.

- `esp_efuse_write_field_cnt()` - writes a required count of bits as "1".

- `esp_efuse_get_field_size()` - returns the number of bits by the field name.

- `esp_efuse_read_reg()` - returns value of eFuse register.

- `esp_efuse_write_reg()` - writes value to eFuse register.

- `esp_efuse_get_coding_scheme()` - returns eFuse coding scheme for blocks.

- `esp_efuse_read_block()` - reads a key from an eFuse block starting at the offset with required size.

- `esp_efuse_write_block()` - writes a key to an eFuse block starting at the offset with required size.

- `esp_efuse_batch_write_begin()` - set the batch mode of writing fields.

- `esp_efuse_batch_write_commit()` - writes all prepared data for batch writing mode and reset the batch writing mode.

- `esp_efuse_batch_write_cancel()` - reset the batch writing mode and prepared data.

- `esp_efuse_get_key_dis_read()` - Returns a read protection for the key block.

- `esp_efuse_set_key_dis_read()` - Sets a read protection for the key block.

- `esp_efuse_get_key_dis_write()` - Returns a write protection for the key block.

- `esp_efuse_set_key_dis_write()` - Sets a write protection for the key block.

- `esp_efuse_get_key_purpose()` - Returns the current purpose set for an eFuse key block.

- `esp_efuse_write_key()` - Programs a block of key data to an eFuse block.

- `esp_efuse_write_keys()` - Programs keys to unused eFuse blocks.

- `esp_efuse_find_purpose()` - Finds a key block with the particular purpose set.

- `esp_efuse_get_keypurpose_dis_write()` - Returns a write protection of the key purpose field for an eFuse key block (for esp32 always true).

- `esp_efuse_key_block_unused()` - Returns true if the key block is unused, false otherwise.

- `esp_efuse_destroy_block()` - Destroys the data in this eFuse block. There are two things to do: (1) if write protection is not set, then the remaining unset bits are burned, (2) set read protection for this block if it is not locked.

- `esp_efuse_token_dump()` - Generates a compact, single-line eFuse token (`EFSR`, `EFSW`, or `EFSRW`) that can be copied from device logs and decoded on the host with `espefuse --token ...` (useful when direct eFuse access is not available).

- `esp_efuse_token_burn()` - Applies an `EFSW` token on the device by burning the staged eFuse writes encoded in the token (other token types are rejected).

For frequently used fields, special functions are made, like this `esp_efuse_get_pkg_ver()`.

## eFuse API for Keys

EFUSE_BLK_KEY0 - EFUSE_BLK_KEY5 are intended to keep up to 6 keys with a length of 256-bits. Each key has an `ESP_EFUSE_KEY_PURPOSE_x` field which defines the purpose of these keys. The purpose field is described in `esp_efuse_purpose_t`.

The purposes like `ESP_EFUSE_KEY_PURPOSE_XTS_AES_...` are used for flash encryption.

The purposes like `ESP_EFUSE_KEY_PURPOSE_SECURE_BOOT_DIGEST...` are used for secure boot.

There are some eFuse APIs useful to work with states of keys:

- `esp_efuse_get_purpose_field()` - Returns a pointer to a key purpose for an eFuse key block.

- `esp_efuse_get_key()` - Returns a pointer to a key block.

- `esp_efuse_set_key_purpose()` - Sets a key purpose for an eFuse key block.

- `esp_efuse_set_keypurpose_dis_write()` - Sets a write protection of the key purpose field for an eFuse key block.

- `esp_efuse_find_unused_key_block()` - Search for an unused key block and return the first one found.

- `esp_efuse_count_unused_key_blocks()` - Returns the number of unused eFuse key blocks in the range EFUSE_BLK_KEY0 to EFUSE_BLK_KEY_MAX

- `esp_efuse_get_digest_revoke()` - Returns the status of the Secure Boot public key digest revocation bit.

- `esp_efuse_set_digest_revoke()` - Sets the Secure Boot public key digest revocation bit.

- `esp_efuse_get_write_protect_of_digest_revoke()` - Returns a write protection of the Secure Boot public key digest revocation bit.

- `esp_efuse_set_write_protect_of_digest_revoke()` - Sets a write protection of the Secure Boot public key digest revocation bit.

## How to Add a New Field

1. Find free bits for field. Refer to the `esp_efuse_table.csv` file, running `idf.py show-efuse-table`, or running the following command:

    $ ./efuse_table_gen.py --idf_target esp32h4 esp32h4/esp_efuse_table.csv --info

    Parsing efuse CSV input file esp32h4/esp_efuse_table.csv ...
    Verifying efuse table...
    Max number of bits in BLK 256
    Sorted efuse table:
    #       field_name                      efuse_block     bit_start       bit_count
    1       WR_DIS                          EFUSE_BLK0         0               32
    2       WR_DIS.RD_DIS                   EFUSE_BLK0         0               1
    3       WR_DIS.KM_DISABLE_DEPLOY_MODE   EFUSE_BLK0         1               1
    4       WR_DIS.KM_RND_SWITCH_CYCLE      EFUSE_BLK0         1               1
    5       WR_DIS.KM_DEPLOY_ONLY_ONCE      EFUSE_BLK0         1               1
    6       WR_DIS.FORCE_USE_KEY_MANAGER_KEY        EFUSE_BLK0         1               1
    7       WR_DIS.FORCE_DISABLE_SW_INIT_KEY        EFUSE_BLK0         1               1
    8       WR_DIS.KM_XTS_KEY_LENGTH_256    EFUSE_BLK0         1               1
    9       WR_DIS.LOCK_KM_KEY              EFUSE_BLK0         1               1
    10      WR_DIS.DIS_USB_JTAG             EFUSE_BLK0         2               1
    11      WR_DIS.DIS_FORCE_DOWNLOAD       EFUSE_BLK0         2               1
    12      WR_DIS.SPI_DOWNLOAD_MSPI_DIS    EFUSE_BLK0         2               1
    13      WR_DIS.DIS_TWAI                 EFUSE_BLK0         2               1
    14      WR_DIS.JTAG_SEL_ENABLE          EFUSE_BLK0         2               1
    15      WR_DIS.DIS_PAD_JTAG             EFUSE_BLK0         2               1
    16      WR_DIS.DIS_DOWNLOAD_MANUAL_ENCRYPT      EFUSE_BLK0         2               1
    17      WR_DIS.PVT_GLITCH_EN            EFUSE_BLK0         2               1
    18      WR_DIS.PVT_GLITCH_MODE          EFUSE_BLK0         2               1
    19      WR_DIS.SPI_BOOT_CRYPT_CNT       EFUSE_BLK0         4               1
    20      WR_DIS.SECURE_BOOT_KEY_REVOKE0  EFUSE_BLK0         5               1
    21      WR_DIS.SECURE_BOOT_KEY_REVOKE1  EFUSE_BLK0         6               1
    22      WR_DIS.SECURE_BOOT_KEY_REVOKE2  EFUSE_BLK0         7               1
    23      WR_DIS.KEY_PURPOSE_0            EFUSE_BLK0         8               1
    24      WR_DIS.KEY_PURPOSE_1            EFUSE_BLK0         9               1
    25      WR_DIS.KEY_PURPOSE_2            EFUSE_BLK0         10              1
    26      WR_DIS.KEY_PURPOSE_3            EFUSE_BLK0         11              1
    27      WR_DIS.KEY_PURPOSE_4            EFUSE_BLK0         12              1
    28      WR_DIS.KEY_PURPOSE_5            EFUSE_BLK0         13              1
    29      WR_DIS.SEC_DPA_LEVEL            EFUSE_BLK0         14              1
    30      WR_DIS.XTS_DPA_PSEUDO_LEVEL     EFUSE_BLK0         14              1
    31      WR_DIS.XTS_DPA_CLK_ENABLE       EFUSE_BLK0         14              1
    32      WR_DIS.ECC_FORCE_CONST_TIME     EFUSE_BLK0         14              1
    33      WR_DIS.SECURE_BOOT_SHA384_EN    EFUSE_BLK0         14              1
    34      WR_DIS.SECURE_BOOT_EN           EFUSE_BLK0         15              1
    35      WR_DIS.SECURE_BOOT_AGGRESSIVE_REVOKE    EFUSE_BLK0         16              1
    36      WR_DIS.FLASH_TPUW               EFUSE_BLK0         18              1
    37      WR_DIS.DIS_DOWNLOAD_MODE        EFUSE_BLK0         18              1
    38      WR_DIS.DIS_DIRECT_BOOT          EFUSE_BLK0         18              1
    39      WR_DIS.DIS_USB_SERIAL_JTAG_ROM_PRINT    EFUSE_BLK0         18              1
    40      WR_DIS.DIS_USB_SERIAL_JTAG_DOWNLOAD_MODE        EFUSE_BLK0         18              1
    41      WR_DIS.ENABLE_SECURITY_DOWNLOAD         EFUSE_BLK0         18              1
    42      WR_DIS.UART_PRINT_CONTROL       EFUSE_BLK0         18              1
    43      WR_DIS.FORCE_SEND_RESUME        EFUSE_BLK0         18              1
    44      WR_DIS.SECURE_VERSION           EFUSE_BLK0         18              1
    45      WR_DIS.HUK_GEN_STATE            EFUSE_BLK0         19              1
    46      WR_DIS.BLK1                     EFUSE_BLK0         20              1
    47      WR_DIS.MAC                      EFUSE_BLK0         20              1
    48      WR_DIS.MAC_EXT                  EFUSE_BLK0         20              1
    49      WR_DIS.PVT_LIMIT                EFUSE_BLK0         20              1
    50      WR_DIS.PVT_CELL_SELECT          EFUSE_BLK0         20              1
    51      WR_DIS.PVT_PUMP_LIMIT           EFUSE_BLK0         20              1
    52      WR_DIS.PUMP_DRV                 EFUSE_BLK0         20              1
    53      WR_DIS.WDT_DELAY_SEL            EFUSE_BLK0         20              1
    54      WR_DIS.HYS_EN_PAD               EFUSE_BLK0         20              1
    55      WR_DIS.PVT_GLITCH_CHARGE_RESET  EFUSE_BLK0         20              1
    56      WR_DIS.VDD_SPI_LDO_ADJUST       EFUSE_BLK0         20              1
    57      WR_DIS.FLASH_LDO_POWER_SEL      EFUSE_BLK0         20              1
    58      WR_DIS.WAFER_VERSION_MINOR      EFUSE_BLK0         20              1
    59      WR_DIS.WAFER_VERSION_MAJOR      EFUSE_BLK0         20              1
    60      WR_DIS.DISABLE_WAFER_VERSION_MAJOR      EFUSE_BLK0         20              1
    61      WR_DIS.DISABLE_BLK_VERSION_MAJOR        EFUSE_BLK0         20              1
    62      WR_DIS.BLK_VERSION_MINOR        EFUSE_BLK0         20              1
    63      WR_DIS.BLK_VERSION_MAJOR        EFUSE_BLK0         20              1
    64      WR_DIS.FLASH_CAP                EFUSE_BLK0         20              1
    65      WR_DIS.FLASH_VENDOR             EFUSE_BLK0         20              1
    66      WR_DIS.PSRAM_CAP                EFUSE_BLK0         20              1
    67      WR_DIS.PSRAM_VENDOR             EFUSE_BLK0         20              1
    68      WR_DIS.TEMP                     EFUSE_BLK0         20              1
    69      WR_DIS.PKG_VERSION              EFUSE_BLK0         20              1
    70      WR_DIS.PVT_DBIAS                EFUSE_BLK0         20              1
    71      WR_DIS.ADJUST_1V2               EFUSE_BLK0         20              1
    72      WR_DIS.ADJUST_1V8               EFUSE_BLK0         20              1
    73      WR_DIS.ACTIVE_DCDC_1V25         EFUSE_BLK0         20              1
    74      WR_DIS.ACTIVE_DCDC_1V35         EFUSE_BLK0         20              1
    75      WR_DIS.SLP_DCDC                 EFUSE_BLK0         20              1
    76      WR_DIS.LSLP_HP_DRVB             EFUSE_BLK0         20              1
    77      WR_DIS.DSLP_LP_DBIAS            EFUSE_BLK0         20              1
    78      WR_DIS.TEMP_CALIB               EFUSE_BLK0         20              1
    79      WR_DIS.SYS_DATA_PART1           EFUSE_BLK0         21              1
    80      WR_DIS.OPTIONAL_UNIQUE_ID       EFUSE_BLK0         21              1
    81      WR_DIS.OCODE                    EFUSE_BLK0         21              1
    82      WR_DIS.DCDC_OCODE               EFUSE_BLK0         21              1
    83      WR_DIS.VDD_3V4_DOUT             EFUSE_BLK0         21              1
    84      WR_DIS.ADC1_AVE_INITCODE_ATTEN0         EFUSE_BLK0         21              1
    85      WR_DIS.ADC1_AVE_INITCODE_ATTEN1         EFUSE_BLK0         21              1
    86      WR_DIS.ADC1_AVE_INITCODE_ATTEN2         EFUSE_BLK0         21              1
    87      WR_DIS.ADC1_AVE_INITCODE_ATTEN3         EFUSE_BLK0         21              1
    88      WR_DIS.ADC1_HI_DOUT_ATTEN0      EFUSE_BLK0         21              1
    89      WR_DIS.ADC1_HI_DOUT_ATTEN1      EFUSE_BLK0         21              1
    90      WR_DIS.ADC1_HI_DOUT_ATTEN2      EFUSE_BLK0         21              1
    91      WR_DIS.ADC1_HI_DOUT_ATTEN3      EFUSE_BLK0         21              1
    92      WR_DIS.ADC1_CH0_ATTEN0_INITCODE_DIFF    EFUSE_BLK0         21              1
    93      WR_DIS.ADC1_CH1_ATTEN0_INITCODE_DIFF    EFUSE_BLK0         21              1
    94      WR_DIS.ADC1_CH2_ATTEN0_INITCODE_DIFF    EFUSE_BLK0         21              1
    95      WR_DIS.ADC1_CH3_ATTEN0_INITCODE_DIFF    EFUSE_BLK0         21              1
    96      WR_DIS.ADC1_CH4_ATTEN0_INITCODE_DIFF    EFUSE_BLK0         21              1
    97      WR_DIS.INITCODE_DIFF_1P8_3P3    EFUSE_BLK0         21              1
    98      WR_DIS.HI_DOUT_DIFF_1P8_3P3     EFUSE_BLK0         21              1
    99      WR_DIS.BLOCK_USR_DATA           EFUSE_BLK0         22              1
    100     WR_DIS.CUSTOM_MAC               EFUSE_BLK0         22              1
    101     WR_DIS.BLOCK_KEY0               EFUSE_BLK0         23              1
    102     WR_DIS.BLOCK_KEY1               EFUSE_BLK0         24              1
    103     WR_DIS.BLOCK_KEY2               EFUSE_BLK0         25              1
    104     WR_DIS.BLOCK_KEY3               EFUSE_BLK0         26              1
    105     WR_DIS.BLOCK_KEY4               EFUSE_BLK0         27              1
    106     WR_DIS.BLOCK_KEY5               EFUSE_BLK0         28              1
    107     WR_DIS.BLOCK_SYS_DATA2          EFUSE_BLK0         29              1
    108     WR_DIS.USB_EXCHG_PINS           EFUSE_BLK0         30              1
    109     WR_DIS.USB_OTG_FS_EXCHG_PINS    EFUSE_BLK0         30              1
    110     WR_DIS.USB_PHY_SEL              EFUSE_BLK0         30              1
    111     WR_DIS.SOFT_DIS_JTAG            EFUSE_BLK0         31              1
    112     RD_DIS                          EFUSE_BLK0         32              7
    113     RD_DIS.BLOCK_KEY0               EFUSE_BLK0         32              1
    114     RD_DIS.BLOCK_KEY1               EFUSE_BLK0         33              1
    115     RD_DIS.BLOCK_KEY2               EFUSE_BLK0         34              1
    116     RD_DIS.BLOCK_KEY3               EFUSE_BLK0         35              1
    117     RD_DIS.BLOCK_KEY4               EFUSE_BLK0         36              1
    118     RD_DIS.BLOCK_KEY5               EFUSE_BLK0         37              1
    119     RD_DIS.BLOCK_SYS_DATA2          EFUSE_BLK0         38              1
    120     DIS_USB_JTAG                    EFUSE_BLK0         39              1
    121     DIS_FORCE_DOWNLOAD              EFUSE_BLK0         41              1
    122     SPI_DOWNLOAD_MSPI_DIS           EFUSE_BLK0         42              1
    123     DIS_TWAI                        EFUSE_BLK0         43              1
    124     JTAG_SEL_ENABLE                 EFUSE_BLK0         44              1
    125     DIS_PAD_JTAG                    EFUSE_BLK0         45              1
    126     DIS_DOWNLOAD_MANUAL_ENCRYPT     EFUSE_BLK0         46              1
    127     PVT_GLITCH_EN                   EFUSE_BLK0         50              1
    128     PVT_GLITCH_MODE                 EFUSE_BLK0         52              2
    129     DIS_CORE1                       EFUSE_BLK0         54              1
    130     SPI_BOOT_CRYPT_CNT              EFUSE_BLK0         55              3
    131     SECURE_BOOT_KEY_REVOKE0         EFUSE_BLK0         58              1
    132     SECURE_BOOT_KEY_REVOKE1         EFUSE_BLK0         59              1
    133     SECURE_BOOT_KEY_REVOKE2         EFUSE_BLK0         60              1
    134     KEY_PURPOSE_0                   EFUSE_BLK0         64              5
    135     KEY_PURPOSE_1                   EFUSE_BLK0         69              5
    136     KEY_PURPOSE_2                   EFUSE_BLK0         74              5
    137     KEY_PURPOSE_3                   EFUSE_BLK0         79              5
    138     KEY_PURPOSE_4                   EFUSE_BLK0         84              5
    139     KEY_PURPOSE_5                   EFUSE_BLK0         89              5
    140     SEC_DPA_LEVEL                   EFUSE_BLK0         94              2
    141     XTS_DPA_PSEUDO_LEVEL            EFUSE_BLK0         96              2
    142     XTS_DPA_CLK_ENABLE              EFUSE_BLK0         98              1
    143     ECC_FORCE_CONST_TIME            EFUSE_BLK0         99              1
    144     SECURE_BOOT_SHA384_EN           EFUSE_BLK0        100              1
    145     SECURE_BOOT_EN                  EFUSE_BLK0        101              1
    146     SECURE_BOOT_AGGRESSIVE_REVOKE   EFUSE_BLK0        102              1
    147     KM_DISABLE_DEPLOY_MODE          EFUSE_BLK0        103              5
    148     KM_RND_SWITCH_CYCLE             EFUSE_BLK0        108              2
    149     KM_DEPLOY_ONLY_ONCE             EFUSE_BLK0        110              5
    150     FORCE_USE_KEY_MANAGER_KEY       EFUSE_BLK0        115              5
    151     FORCE_DISABLE_SW_INIT_KEY       EFUSE_BLK0        120              1
    152     KM_XTS_KEY_LENGTH_256           EFUSE_BLK0        121              1
    153     LOCK_KM_KEY                     EFUSE_BLK0        122              1
    154     FLASH_TPUW                      EFUSE_BLK0        123              3
    155     DIS_DOWNLOAD_MODE               EFUSE_BLK0        127              1
    156     DIS_DIRECT_BOOT                 EFUSE_BLK0        128              1
    157     DIS_USB_SERIAL_JTAG_ROM_PRINT   EFUSE_BLK0        129              1
    158     DIS_USB_SERIAL_JTAG_DOWNLOAD_MODE       EFUSE_BLK0        130              1
    159     ENABLE_SECURITY_DOWNLOAD        EFUSE_BLK0        131              1
    160     UART_PRINT_CONTROL              EFUSE_BLK0        132              2
    161     FORCE_SEND_RESUME               EFUSE_BLK0        134              1
    162     SECURE_VERSION                  EFUSE_BLK0        135              16
    163     HUK_GEN_STATE                   EFUSE_BLK0        151              5
    164     FLASH_LDO_EFUSE_SEL             EFUSE_BLK0        156              1
    165     USB_EXCHG_PINS                  EFUSE_BLK0        168              1
    166     USB_OTG_FS_EXCHG_PINS           EFUSE_BLK0        169              1
    167     USB_PHY_SEL                     EFUSE_BLK0        170              1
    168     SOFT_DIS_JTAG                   EFUSE_BLK0        171              3
    169     IO_LDO_ADJUST                   EFUSE_BLK0        174              8
    170     IO_LDO_1P8                      EFUSE_BLK0        182              1
    171     DCDC_CCM_EN                     EFUSE_BLK0        183              1
    172     MAC                             EFUSE_BLK1         0               8
    173     MAC                             EFUSE_BLK1         8               8
    174     MAC                             EFUSE_BLK1         16              8
    175     MAC                             EFUSE_BLK1         24              8
    176     MAC                             EFUSE_BLK1         32              8
    177     MAC                             EFUSE_BLK1         40              8
    178     MAC_EXT                         EFUSE_BLK1         48              8
    179     MAC_EXT                         EFUSE_BLK1         56              8
    180     PVT_LIMIT                       EFUSE_BLK1         64              16
    181     PVT_CELL_SELECT                 EFUSE_BLK1         80              7
    182     PVT_PUMP_LIMIT                  EFUSE_BLK1         87              8
    183     PUMP_DRV                        EFUSE_BLK1         96              4
    184     WDT_DELAY_SEL                   EFUSE_BLK1        100              2
    185     HYS_EN_PAD                      EFUSE_BLK1        102              1
    186     PVT_GLITCH_CHARGE_RESET         EFUSE_BLK1        103              1
    187     VDD_SPI_LDO_ADJUST              EFUSE_BLK1        105              8
    188     FLASH_LDO_POWER_SEL             EFUSE_BLK1        113              1
    189     WAFER_VERSION_MINOR             EFUSE_BLK1        114              4
    190     WAFER_VERSION_MAJOR             EFUSE_BLK1        118              2
    191     DISABLE_WAFER_VERSION_MAJOR     EFUSE_BLK1        120              1
    192     DISABLE_BLK_VERSION_MAJOR       EFUSE_BLK1        121              1
    193     BLK_VERSION_MINOR               EFUSE_BLK1        122              3
    194     BLK_VERSION_MAJOR               EFUSE_BLK1        125              2
    195     FLASH_CAP                       EFUSE_BLK1        127              3
    196     FLASH_VENDOR                    EFUSE_BLK1        130              3
    197     PSRAM_CAP                       EFUSE_BLK1        133              3
    198     PSRAM_VENDOR                    EFUSE_BLK1        136              2
    199     TEMP                            EFUSE_BLK1        138              2
    200     PKG_VERSION                     EFUSE_BLK1        140              3
    201     PVT_DBIAS                       EFUSE_BLK1        143              5
    202     ADJUST_1V2                      EFUSE_BLK1        148              4
    203     ADJUST_1V8                      EFUSE_BLK1        152              4
    204     ACTIVE_DCDC_1V25                EFUSE_BLK1        156              4
    205     ACTIVE_DCDC_1V35                EFUSE_BLK1        160              4
    206     SLP_DCDC                        EFUSE_BLK1        164              5
    207     LSLP_HP_DRVB                    EFUSE_BLK1        169              5
    208     DSLP_LP_DBIAS                   EFUSE_BLK1        174              2
    209     TEMP_CALIB                      EFUSE_BLK1        176              10
    210     SYS_DATA_PART2                  EFUSE_BLK10        0              256
    211     OPTIONAL_UNIQUE_ID              EFUSE_BLK2         0              128
    212     OCODE                           EFUSE_BLK2        128              8
    213     DCDC_OCODE                      EFUSE_BLK2        136              8
    214     VDD_3V4_DOUT                    EFUSE_BLK2        144              10
    215     ADC1_AVE_INITCODE_ATTEN0        EFUSE_BLK2        154              9
    216     ADC1_AVE_INITCODE_ATTEN1        EFUSE_BLK2        163              9
    217     ADC1_AVE_INITCODE_ATTEN2        EFUSE_BLK2        172              9
    218     ADC1_AVE_INITCODE_ATTEN3        EFUSE_BLK2        181              9
    219     ADC1_HI_DOUT_ATTEN0             EFUSE_BLK2        190              9
    220     ADC1_HI_DOUT_ATTEN1             EFUSE_BLK2        199              9
    221     ADC1_HI_DOUT_ATTEN2             EFUSE_BLK2        208              9
    222     ADC1_HI_DOUT_ATTEN3             EFUSE_BLK2        217              9
    223     ADC1_CH0_ATTEN0_INITCODE_DIFF   EFUSE_BLK2        226              3
    224     ADC1_CH1_ATTEN0_INITCODE_DIFF   EFUSE_BLK2        229              3
    225     ADC1_CH2_ATTEN0_INITCODE_DIFF   EFUSE_BLK2        232              3
    226     ADC1_CH3_ATTEN0_INITCODE_DIFF   EFUSE_BLK2        235              3
    227     ADC1_CH4_ATTEN0_INITCODE_DIFF   EFUSE_BLK2        238              3
    228     INITCODE_DIFF_1P8_3P3           EFUSE_BLK2        241              5
    229     HI_DOUT_DIFF_1P8_3P3            EFUSE_BLK2        246              5
    230     USER_DATA                       EFUSE_BLK3         0              256
    231     USER_DATA.MAC_CUSTOM            EFUSE_BLK3        200              48
    232     KEY0                            EFUSE_BLK4         0              256
    233     KEY1                            EFUSE_BLK5         0              256
    234     KEY2                            EFUSE_BLK6         0              256
    235     KEY3                            EFUSE_BLK7         0              256
    236     KEY4                            EFUSE_BLK8         0              256
    237     KEY5                            EFUSE_BLK9         0              256

    Used bits in efuse table:
    EFUSE_BLK0
    [0 31] [0 1] [1 1] ... [50 50] [52 60] [64 125] [127 156] [168 183]

    EFUSE_BLK1
    [0 94] [96 103] [105 185]

    EFUSE_BLK10
    [0 255]

    EFUSE_BLK2
    [0 250]

    EFUSE_BLK3
    [0 255] [200 247]

    EFUSE_BLK4
    [0 255]

    EFUSE_BLK5
    [0 255]

    EFUSE_BLK6
    [0 255]

    EFUSE_BLK7
    [0 255]

    EFUSE_BLK8
    [0 255]

    EFUSE_BLK9
    [0 255]

    Note: Not printed ranges are free for using. (bits in EFUSE_BLK0 are reserved for Espressif)

The number of bits not included in square brackets are free (some bits are reserved by Espressif). All fields are checked for overlapping bits.

To add child fields to an existing field, Structured eFuse Fields can be used. The following example demonstrates adding of the fields `SERIAL_NUMBER`, `MODEL_NUMBER` and `HARDWARE_REV` to an existing `USER_DATA` field by using the `.` operator:

    USER_DATA.SERIAL_NUMBER,                  EFUSE_BLK3,    0,  32,
    USER_DATA.MODEL_NUMBER,                   EFUSE_BLK3,    32, 10,
    USER_DATA.HARDWARE_REV,                   EFUSE_BLK3,    42, 10,

In general, to add new eFuse Fields:

1. Add a record for each eFuse field in CSV file.

2. Run the `show_efuse_table` command to check eFuse table.

3. To generate source files run the `efuse_common_table` or `efuse_custom_table` commands.

You may get errors such as `intersects with` or `out of range`. Please see how to solve them in the Structured eFuse Fields article.

## Bit Order

The eFuses bit order is little endian (see the example below), meaning that eFuse bits are read and written from LSB to MSB:

    $ idf.py efuse-dump

    USER_DATA      (BLOCK3          ) [3 ] read_regs: 03020100 07060504 0B0A0908 0F0E0D0C 13121111 17161514 1B1A1918 1F1E1D1C
    BLOCK4         (BLOCK4          ) [4 ] read_regs: 03020100 07060504 0B0A0908 0F0E0D0C 13121111 17161514 1B1A1918 1F1E1D1C

    where is the register representation:

    EFUSE_RD_USR_DATA0_REG = 0x03020100
    EFUSE_RD_USR_DATA1_REG = 0x07060504
    EFUSE_RD_USR_DATA2_REG = 0x0B0A0908
    EFUSE_RD_USR_DATA3_REG = 0x0F0E0D0C
    EFUSE_RD_USR_DATA4_REG = 0x13121111
    EFUSE_RD_USR_DATA5_REG = 0x17161514
    EFUSE_RD_USR_DATA6_REG = 0x1B1A1918
    EFUSE_RD_USR_DATA7_REG = 0x1F1E1D1C

    where is the byte representation:

    byte[0] = 0x00, byte[1] = 0x01, ... byte[3] = 0x03, byte[4] = 0x04, ..., byte[31] = 0x1F

For example, CSV file describes the `USER_DATA` field, which occupies all 256 bits (a whole block).

    USER_DATA,          EFUSE_BLK3,    0,  256,     User data
    USER_DATA.FIELD1,   EFUSE_BLK3,    16,  16,     Field1

    ID,                 EFUSE_BLK4,    8,  3,      ID bit[0..2]
    ,                   EFUSE_BLK4,    16, 2,      ID bit[3..4]
    ,                   EFUSE_BLK4,    32, 3,      ID bit[5..7]

Thus, reading the eFuse `USER_DATA` block written as above gives the following results:

    uint8_t buf[32] = { 0 };
    esp_efuse_read_field_blob(ESP_EFUSE_USER_DATA, &buf, sizeof(buf) * 8);
    // buf[0] = 0x00, buf[1] = 0x01, ... buf[31] = 0x1F

    uint32_t field1 = 0;
    size_t field1_size = ESP_EFUSE_USER_DATA[0]->bit_count; // can be used for this case because it only consists of one entry
    esp_efuse_read_field_blob(ESP_EFUSE_USER_DATA, &field1, field1_size);
    // field1 = 0x0302

    uint32_t field1_1 = 0;
    esp_efuse_read_field_blob(ESP_EFUSE_USER_DATA, &field1_1, 2); // reads only first 2 bits
    // field1 = 0x0002

    uint8_t id = 0;
    size_t id_size = esp_efuse_get_field_size(ESP_EFUSE_ID); // returns 6
    // size_t id_size = ESP_EFUSE_USER_DATA[0]->bit_count; // cannot be used because it consists of 3 entries. It returns 3 not 6
    esp_efuse_read_field_blob(ESP_EFUSE_ID, &id, id_size);
    // id = 0x91
    // b'100 10  001
    //   [3] [2] [3]

    uint8_t id_1 = 0;
    esp_efuse_read_field_blob(ESP_EFUSE_ID, &id_1, 3);
    // id = 0x01
    // b'001

## Get eFuses During Build

There is a way to get the state of eFuses at the build stage of the project. There are two CMake functions for this:

- `espefuse_get_json_summary()` - It calls the `espefuse summary --format json` command and returns a JSON string (it is not stored in a file).

- `espefuse_get_efuse()` - It finds a given eFuse name in the JSON string and returns its property.

The JSON string has the following properties:

    {
        "MAC": {
            "bit_len": 48,
            "block": 0,
            "category": "identity",
            "description": "Factory MAC Address",
            "efuse_type": "bytes:6",
            "name": "MAC",
            "pos": 0,
            "readable": true,
            "value": "94:b9:7e:5a:6e:58 (CRC 0xe2 OK)",
            "word": 1,
            "writeable": true
        },
    }

These functions can be used from a top-level project `CMakeLists.txt` (system/efuse/CMakeLists.txt):

    # ...
    project(hello_world)

    espefuse_get_json_summary(efuse_json)
    espefuse_get_efuse(ret_data ${efuse_json} "MAC" "value")
    message("MAC:" ${ret_data})

The format of the `value` property is the same as shown in `espefuse summary` or `idf.py efuse-summary`.

    MAC:94:b9:7e:5a:6e:58 (CRC 0xe2 OK)

There is an example test system/efuse/CMakeLists.txt which adds a custom target `efuse-filter`. This allows you to run the `idf.py efuse-filter` command to read the required eFuses (specified in the `efuse_names` list) at any time, not just during the project build.

## Debug eFuse & Unit Tests

### Virtual eFuses

The Kconfig option CONFIG_EFUSE_VIRTUAL virtualizes eFuse values inside the eFuse Manager, so writes are emulated and no eFuse values are permanently changed. This can be useful for debugging and unit testing.

During startup, the eFuses are copied to RAM. All eFuse operations (read and write) are performed with RAM instead of the real eFuse registers.

In addition to the CONFIG_EFUSE_VIRTUAL option, there is the CONFIG_EFUSE_VIRTUAL_KEEP_IN_FLASH option that adds a feature to keep eFuses in flash memory. To use this mode, the partition_table should have include an `efuse` partition in `partition.csv`:

    efuse_em, data, efuse,   ,   0x2000,

During startup, the eFuses are copied from flash, or in case where flash is empty, copied from real eFuse to RAM and then write flash. This option allows keeping eFuses after reboots, making it possible to test Secure Boot and Flash Encryption features.

#### Flash Encryption Testing

Flash encryption is a hardware feature that requires the physical burning of eFuses `key` and `FLASH_CRYPT_CNT`. If flash encryption is not actually enabled, then enabling the CONFIG_EFUSE_VIRTUAL_KEEP_IN_FLASH option just provides testing possibilities and does not encrypt anything in the flash, even though the logs indicates that encryption happens.

The `bootloader_flash_write()` is adapted for this purpose. But if flash encryption is already enabled on the chip when the application is run, or if the bootloader is created with the CONFIG_EFUSE_VIRTUAL_KEEP_IN_FLASH option, then the flash encryption/decryption operations will work properly. This means that data are encrypted as it is written into an encrypted flash partition and decrypted when they are read from an encrypted partition.

### `espefuse`

esptool includes a useful tool for reading/writing ESP32-H4 eFuse bits - espefuse.

Part of the functionality of this tool is also provided directly by `idf.py` commands. For example, the `idf.py efuse-summary` command is equivalent to `espefuse summary`.

    idf.py -p PORT efuse-summary

    Executing action: efuse-summary
    (...)

    === Run "summary" command ===
    EFUSE_NAME (Block) Description  = [Meaningful Value] [Readable/Writeable] (Hex Value)
    ----------------------------------------------------------------------------------------
    Config fuses:
    WR_DIS (BLOCK0)                                    Disable programming of individual eFuses           = 0 R/W (0x00000000)
    RD_DIS (BLOCK0)                                    Disable reading from BlOCK4-10                     = 0 R/W (0b0000000)
    DIS_TWAI (BLOCK0)                                  Represents whether TWAI function is disabled or en = False R/W (0b0)
                                                       abled. 1: disabled 0: enabled
    PVT_GLITCH_EN (BLOCK0)                             Represents whether to enable PVT power glitch moni = False R/W (0b0)
                                                       tor function.1:Enable. 0:Disable
    PVT_GLITCH_MODE (BLOCK0)                           Use to configure glitch mode                       = 0 R/W (0b00)
    DIS_CORE1 (BLOCK0)                                 Represents whether the CPU-Core1 is disabled.  1:  = False R/W (0b0)
                                                       Disabled.  0: Not disable
    ECC_FORCE_CONST_TIME (BLOCK0)                      Represents whether to force ecc to use const-time  = False R/W (0b0)
                                                       calculation mode.  1: Enable.  0: Disable
    KM_DISABLE_DEPLOY_MODE (BLOCK0)                    Represents whether the new key deployment of key m = 0 R/W (0b00000)
                                                       anager is disabled. Bit0: Represents whether the n
                                                       ew ECDSA key deployment is disabled0: Enabled1: Di
                                                       sabledBit1: Represents whether the new XTS-AES (fl
                                                       ash and PSRAM) key deployment is disabled0: Enable
                                                       d1: DisabledBit2: Represents whether the new HMAC
                                                       key deployment is disabled0: Enabled1: DisabledBit
                                                       3: Represents whether the new DS key deployment is
                                                        disabled0: Enabled1: Disabled
    KM_RND_SWITCH_CYCLE (BLOCK0)                       Represents the cycle at which the Key Manager swit = 0 R/W (0b00)
                                                       ches random numbers.0: Controlled by the \hyperref
                                                       [fielddesc:KEYMNGRNDSWITCHCYCLE]{KEYMNG\_RND\_SWIT
                                                       CH\_CYCLE} register. For more information; please
                                                       refer to Chapter \ref{mod:keymng} \textit{\nameref
                                                       {mod:keymng}}1: 8 Key Manager clock cycles2: 16 Ke
                                                       y Manager clock cycles3: 32 Key Manager clock cycl
                                                       es
    KM_DEPLOY_ONLY_ONCE (BLOCK0)                       Represents whether the corresponding key can be de = 0 R/W (0b00000)
                                                       ployed only once.Bit0: Represents whether the ECDS
                                                       A key can be deployed only once0: The key can be d
                                                       eployed multiple times1: The key can be deployed o
                                                       nly onceBit1: Represents whether the XTS-AES (flas
                                                       h and PSRAM) key can be deployed only once0: The k
                                                       ey can be deployed multiple times1: The key can be
                                                        deployed only onceBit2: Represents whether the HM
                                                       AC key can be deployed only once0: The key can be
                                                       deployed multiple times1: The key can be deployed
                                                       only onceBit3: Represents whether the DS key can b
                                                       e deployed only once0: The key can be deployed
                                                       multiple times1: The key can be deployed only once
    DIS_DIRECT_BOOT (BLOCK0)                           Represents whether direct boot mode is disabled or = False R/W (0b0)
                                                        enabled. 1: disabled 0: enabled
    UART_PRINT_CONTROL (BLOCK0)                        Represents the type of UART printing. 00: force en = 0 R/W (0b00)
                                                       able printing 01: enable printing when GPIO8 is re
                                                       set at low level 10: enable printing when GPIO8 is
                                                        reset at high level 11: force disable printing
    HUK_GEN_STATE (BLOCK0)                             Represents whether the HUK generate mode is valid. = 0 R/W (0b00000)
                                                       Odd count of bits with a value of 1: InvalidEven c
                                                       ount of bits with a value of 1: Valid
    DCDC_CCM_EN (BLOCK0)                               Represents whether change DCDC to CCM mode         = False R/W (0b0)
    PVT_LIMIT (BLOCK1)                                 Power glitch monitor threthold                     = 0 R/W (0x0000)
    PVT_CELL_SELECT (BLOCK1)                           Power glitch monitor PVT cell select               = 0 R/W (0b0000000)
    PVT_PUMP_LIMIT (BLOCK1)                            Use to configure voltage monitor limit for charge  = 0 R/W (0x00)
                                                       pump
    PUMP_DRV (BLOCK1)                                  Use to configure charge pump voltage gain          = 0 R/W (0x0)
    HYS_EN_PAD (BLOCK1)                                Represents whether the hysteresis function of      = False R/W (0b0)
                                                       corresponding PAD is enabled. 1: enabled 0:disabled
    PVT_GLITCH_CHARGE_RESET (BLOCK1)                   Represents whether to trigger reset or charge pump = False R/W (0b0)
                                                        when PVT power glitch happened.1:Trigger charge p
                                                       ump. 0:Trigger reset
    PSRAM_CAP (BLOCK1)                                 Psram capacity                                     = 0 R/W (0b000)
    PSRAM_VENDOR (BLOCK1)                              Psram vendor                                       = 0 R/W (0b00)
    TEMP (BLOCK1)                                      Temp (die embedded inside)                         = 0 R/W (0b00)
    ADJUST_1V2 (BLOCK1)                                SPI LDO adjust of 1.2v                             = 0 R/W (0x0)
    ADJUST_1V8 (BLOCK1)                                SPI LDO adjust of 1.8v                             = 0 R/W (0x0)
    ACTIVE_DCDC_1V25 (BLOCK1)                          DCDC-DCDC DBIAS of 1.25v                           = 0 R/W (0x0)
    ACTIVE_DCDC_1V35 (BLOCK1)                          DCDC-DCDC DBIAS of 1.35v                           = 0 R/W (0x0)
    SLP_DCDC (BLOCK1)                                  DCDC DBIAS in sleep                                = 0 R/W (0b00000)
    VDD_3V4_DOUT (BLOCK2)                              ADC dout of vdd 3.4v                               = 0 R/W (0b0000000000)
    INITCODE_DIFF_1P8_3P3 (BLOCK2)                     Initcode diff between IO LDO 1.8v and 3.3v         = 0 R/W (0b00000)
    HI_DOUT_DIFF_1P8_3P3 (BLOCK2)                      HI dout diff between IO LDO 1.8v and 3.3v          = 0 R/W (0b00000)
    BLOCK_USR_DATA (BLOCK3)                            User data
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W
    BLOCK_SYS_DATA2 (BLOCK10)                          System data part 2 (reserved)
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W

    Flash fuses:
    FLASH_TPUW (BLOCK0)                                Represents the flash waiting time after power-up;  = 0 R/W (0b000)
                                                       in unit of ms. When the value less than 15; the wa
                                                       iting time is the programmed value. Otherwise; the
                                                        waiting time is 2 times the programmed value
    FORCE_SEND_RESUME (BLOCK0)                         Represents whether ROM code is forced to send a re = False R/W (0b0)
                                                       sume command during SPI boot. 1: forced 0:not forc
                                                       ed
    FLASH_LDO_EFUSE_SEL (BLOCK0)                       Represents whether to select efuse control flash l = False R/W (0b0)
                                                       do default voltage.  1 : efuse 0 : strapping
    FLASH_LDO_POWER_SEL (BLOCK1)                       Represents which flash ldo be select: 1: FLASH LDO = False R/W (0b0)
                                                        1P2 0 : FLASH LDO 1P8
    FLASH_CAP (BLOCK1)                                 Flash capacity                                     = 0 R/W (0b000)
    FLASH_VENDOR (BLOCK1)                              Flash vendor                                       = 0 R/W (0b000)

    Identity fuses:
    WAFER_VERSION_MINOR (BLOCK1)                       Minor chip version                                 = 1 R/W (0x1)
    WAFER_VERSION_MAJOR (BLOCK1)                       Major chip version                                 = 0 R/W (0b00)
    DISABLE_WAFER_VERSION_MAJOR (BLOCK1)               Disables check of wafer version major              = False R/W (0b0)
    DISABLE_BLK_VERSION_MAJOR (BLOCK1)                 Disables check of blk version major                = False R/W (0b0)
    BLK_VERSION_MINOR (BLOCK1)                         BLK_VERSION_MINOR of BLOCK2                        = 0 R/W (0b000)
    BLK_VERSION_MAJOR (BLOCK1)                         BLK_VERSION_MAJOR of BLOCK2                        = 0 R/W (0b00)
    PKG_VERSION (BLOCK1)                               Package version                                    = 0 R/W (0b000)
    OPTIONAL_UNIQUE_ID (BLOCK2)                        Optional unique 128-bit ID
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W

    Jtag fuses:
    JTAG_SEL_ENABLE (BLOCK0)                           Represents whether the selection between usb_to_jt = False R/W (0b0)
                                                       ag and pad_to_jtag through strapping gpio15 when b
                                                       oth EFUSE_DIS_PAD_JTAG and EFUSE_DIS_USB_JTAG are
                                                       equal to 0 is enabled or disabled. 1: enabled 0: d
                                                       isabled
    DIS_PAD_JTAG (BLOCK0)                              Represents whether JTAG is disabled in the hard wa = False R/W (0b0)
                                                       y(permanently). 1: disabled 0: enabled
    SOFT_DIS_JTAG (BLOCK0)                             Represents whether JTAG is disabled in soft way. O = 0 R/W (0b000)
                                                       dd number: disabled Even number: enabled

    Mac fuses:
    MAC (BLOCK1)                                       MAC address
       = 30:ed:a0:ed:57:cc (OK) R/W
    MAC_EXT (BLOCK1)                                   Represents the extended bits of MAC address        = 00:00 (OK) R/W
    CUSTOM_MAC (BLOCK3)                                Custom MAC
       = 00:00:00:00:00:00 (OK) R/W
    MAC_EUI64 (BLOCK1)                                 calc MAC_EUI64 = MAC[0]:MAC[1]:MAC[2]:MAC_EXT[0]:M
       = 30:ed:a0:00:00:ed:57:cc (OK) R/W
                                                       AC_EXT[1]:MAC[3]:MAC[4]:MAC[5]

    Security fuses:
    DIS_FORCE_DOWNLOAD (BLOCK0)                        Represents whether the function that forces chip i = False R/W (0b0)
                                                       nto download mode is disabled or enabled. 1: disab
                                                       led 0: enabled
    SPI_DOWNLOAD_MSPI_DIS (BLOCK0)                     Represents whether SPI0 controller during boot_mod = False R/W (0b0)
                                                       e_download is disabled or enabled. 1: disabled 0:
                                                       enabled
    DIS_DOWNLOAD_MANUAL_ENCRYPT (BLOCK0)               Represents whether flash encrypt function is disab = False R/W (0b0)
                                                       led or enabled(except in SPI boot mode). 1: disabled
                                                       0: enabled
    SPI_BOOT_CRYPT_CNT (BLOCK0)                        Enables flash encryption when 1 or 3 bits are set  = Disable R/W (0b000)
                                                       and disables otherwise
    SECURE_BOOT_KEY_REVOKE0 (BLOCK0)                   Revoke 1st secure boot key                         = False R/W (0b0)
    SECURE_BOOT_KEY_REVOKE1 (BLOCK0)                   Revoke 2nd secure boot key                         = False R/W (0b0)
    SECURE_BOOT_KEY_REVOKE2 (BLOCK0)                   Revoke 3rd secure boot key                         = False R/W (0b0)
    KEY_PURPOSE_0 (BLOCK0)                             Represents the purpose of Key0                     = USER R/W (0b00000)
    KEY_PURPOSE_1 (BLOCK0)                             Represents the purpose of Key1                     = USER R/W (0b00000)
    KEY_PURPOSE_2 (BLOCK0)                             Represents the purpose of Key2                     = USER R/W (0b00000)
    KEY_PURPOSE_3 (BLOCK0)                             Represents the purpose of Key3                     = USER R/W (0b00000)
    KEY_PURPOSE_4 (BLOCK0)                             Represents the purpose of Key4                     = USER R/W (0b00000)
    KEY_PURPOSE_5 (BLOCK0)                             Represents the purpose of Key5                     = USER R/W (0b00000)
    SEC_DPA_LEVEL (BLOCK0)                             Represents the spa secure level by configuring the = 0 R/W (0b00)
                                                        clock random divide mode
    XTS_DPA_PSEUDO_LEVEL (BLOCK0)                      Represents the pseudo round level of xts-aes anti- = 0 R/W (0b00)
                                                       dpa attack. 3: High. 2: Moderate 1. Low 0: Disabled
    XTS_DPA_CLK_ENABLE (BLOCK0)                        Represents whether xts-aes anti-dpa attack clock i = False R/W (0b0)
                                                       s enabled. 1. Enable. 0: Disable.
    SECURE_BOOT_SHA384_EN (BLOCK0)                     Represents if the chip supports Secure Boot using  = False R/W (0b0)
                                                       SHA-384
    SECURE_BOOT_EN (BLOCK0)                            Represents whether secure boot is enabled or disab = False R/W (0b0)
                                                       led. 1: enabled 0: disabled
    SECURE_BOOT_AGGRESSIVE_REVOKE (BLOCK0)             Represents whether revoking aggressive secure boot = False R/W (0b0)
                                                        is enabled or disabled. 1: enabled. 0: disabled
    FORCE_USE_KEY_MANAGER_KEY (BLOCK0)                 Represents whether the corresponding key must come = 0 R/W (0b00000)
                                                        from Key Manager. Bit0: Represents whether the EC
                                                       DSA key must come from Key Manager.0: The key does
                                                        not need to come from Key Manager1: The key must
                                                       come from Key ManagerBit1: Represents whether the
                                                       XTS-AES (flash and PSRAM) key must come from Key M
                                                       anager.0: The key does not need to come from Key M
                                                       anager1: The key must come from Key ManagerBit2: R
                                                       epresents whether the HMAC key must come from Key
                                                       Manager.0: The key does not need to come from Key
                                                       Manager1: The key must come from Key ManagerBit3:
                                                       Represents whether the DS key must come from Key M
                                                       anager.0: The key does not need to come from Key M
                                                       anager1: The key must come from Key Manager
    FORCE_DISABLE_SW_INIT_KEY (BLOCK0)                 Represents whether to disable the use of the initi = False R/W (0b0)
                                                       alization key written by software and instead forc
                                                       e use efuse\_init\_key.0: Enable1: Disable
    KM_XTS_KEY_LENGTH_256 (BLOCK0)                     Represents which key flash encryption uses.0: XTS- = False R/W (0b0)
                                                       AES-256 key1: XTS-AES-128 key
    LOCK_KM_KEY (BLOCK0)                               Represents whether the keys in the Key Manager are = False R/W (0b0)
                                                        locked after deployment.0: Not locked1: Locked
    DIS_DOWNLOAD_MODE (BLOCK0)                         Represents whether Download mode is disabled or en = False R/W (0b0)
                                                       abled. 1: disabled 0: enabled
    ENABLE_SECURITY_DOWNLOAD (BLOCK0)                  Represents whether security download is enabled or = False R/W (0b0)
                                                        disabled. 1: enabled 0: disabled
    SECURE_VERSION (BLOCK0)                            Represents the version used by ESP-IDF anti-rollba = 0 R/W (0x0000)
                                                       ck feature
    BLOCK_KEY0 (BLOCK4)
      Purpose: USER
                   Key0 or user data
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W
    BLOCK_KEY1 (BLOCK5)
      Purpose: USER
                   Key1 or user data
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W
    BLOCK_KEY2 (BLOCK6)
      Purpose: USER
                   Key2 or user data
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W
    BLOCK_KEY3 (BLOCK7)
      Purpose: USER
                   Key3 or user data
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W
    BLOCK_KEY4 (BLOCK8)
      Purpose: USER
                   Key4 or user data
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W
    BLOCK_KEY5 (BLOCK9)
      Purpose: USER
                   Key5 or user data
       = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W

    Usb fuses:
    DIS_USB_JTAG (BLOCK0)                              Represents whether the function of usb switch to j = False R/W (0b0)
                                                       tag is disabled or enabled. 1: disabled 0: enabled
    DIS_USB_SERIAL_JTAG_ROM_PRINT (BLOCK0)             Represents whether print from USB-Serial-JTAG is d = False R/W (0b0)
                                                       isabled or enabled. 1: disabled 0: enabled
    DIS_USB_SERIAL_JTAG_DOWNLOAD_MODE (BLOCK0)         Represents whether the USB-Serial-JTAG download fu = False R/W (0b0)
                                                       nction is disabled or enabled. 1: Disable 0: Enabl
                                                       e
    USB_EXCHG_PINS (BLOCK0)                            Represents whether the D+ and D- pins of USB_SERIA = False R/W (0b0)
                                                       L_JTAG PHY is exchanged. 1: exchanged 0: not excha
                                                       nged
    USB_OTG_FS_EXCHG_PINS (BLOCK0)                     Represents whether the D+ and D- pins of USB_OTG_F = False R/W (0b0)
                                                       S PHY is exchanged. 1: exchanged 0: not exchanged
    USB_PHY_SEL (BLOCK0)                               Represents whether to exchange the USB_SERIAL_JTAG = False R/W (0b0)
                                                        PHY with USB_OTG_FS PHY.  1: exchanged.  0: not e
                                                       xchanged

    Vdd fuses:
    VDD_SPI_LDO_ADJUST (BLOCK1)                        Represents configuration of FLASH LDO mode and     = 0 R/W (0x00)
                                                       voltage.

    Wdt fuses:
    WDT_DELAY_SEL (BLOCK1)                             Represents the threshold level of the RTC watchdog = 0 R/W (0b00)
                                                        STG0 timeout. 0: Original threshold configuration
                                                        value of STG0 *2 1: Original threshold configurat
                                                       ion value of STG0 *4 2: Original threshold configu
                                                       ration value of STG0 *8 3: Original threshold conf
                                                       iguration value of STG0 *16

To get a dump for all eFuse registers.

    idf.py -p PORT efuse-dump

    Executing action: efuse-dump
    Running espefuse in directory <project-directory>
    Executing "espefuse dump --chip esp32h4"...
    espefuse v5.3.dev3
    Connecting....
    === Run "dump" command ===
    BLOCK0          (                ) [0 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000
    MAC_SPI_8M_0    (BLOCK1          ) [1 ] dump: a0ed57cc 000030ed 00000000 00040000 00000000 00000000
    BLOCK_SYS_DATA  (BLOCK2          ) [2 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_USR_DATA  (BLOCK3          ) [3 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY0      (BLOCK4          ) [4 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY1      (BLOCK5          ) [5 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY2      (BLOCK6          ) [6 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY3      (BLOCK7          ) [7 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY4      (BLOCK8          ) [8 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY5      (BLOCK9          ) [9 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_SYS_DATA2 (BLOCK10         ) [10] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

## Deferred WR_DIS Burning

`WR_DIS` (Write Disable) is a special eFuse field that implements permanent write-protection. Each bit in `WR_DIS` disables further programming of one (or more) associated eFuse fields. Once a `WR_DIS` bit is burned, its associated fields can no longer be modified.

When burning staged data in BLOCK0, the `WR_DIS` bits are burned separately after all other BLOCK0 data to ensure the burn function can recover from coding errors via its retry mechanism. This approach guarantees that write-protection is applied only after other BLOCK0 data is successfully burned.

## Token Dump

The token dump feature provides a compact, single-line representation of an eFuse state that can be copied from device logs and decoded later on the host. This is designed for cases where reading eFuses directly with host tools is not possible or not convenient (for example, UART download is disabled, secure download is enabled, secure boot/flash encryption is deployed, or the device is remote).

    EFSR:esp32c3:004:AAGAAAEAAAAAAAAEAAAAAAAAAAAAAAAA:AAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAA:AgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA::::::::::epNVBg

A token can represent:

- the currently programmed eFuses (read snapshot, EFSR),

- the staged (not yet burned) write set (write snapshot, EFSW) — in batch write mode you can dump the pending writes before calling `esp_efuse_batch_write_commit()`,

- both the programmed eFuses and the staged writes in a single token (combined snapshot, EFSRW).

Tokens include a CRC32 checksum to detect truncation and accidental modifications.

### Typical Use Cases

- Production/field diagnostics: export the eFuse state from a locked-down device and decode it offline.

- Post-provisioning verification: confirm security configuration and key purposes after manufacturing steps.

- Coding error investigation: capture and share coding-error register snapshots alongside block data.

- Audit and traceability: store a token as a provisioning artifact for later review.

- Staged write transfer: generate `EFSW` in firmware (or on the host) and apply it later using a controlled workflow.

### Supported Workflows

- On the device:

  > - `esp_efuse_token_dump()` — always supports `EFSR` tokens; `EFSW` and `EFSRW` require CONFIG_EFUSE_ENABLE_STAGED_TOKEN_API because they expose staged values that are not yet burned and not yet read-protected.

  > - `esp_efuse_token_burn()` — accepts an `EFSW` token and applies staged writes on the device.

- On the host:

  - `espefuse --token EFS... summary` — decodes tokens and shows the eFuse summary without connecting to a device.

  - `espefuse dump --format EFSR` — generates an `EFSR` token from a connected chip for sharing/backup.

  - `espefuse burn-efuse ... --show-token` — generates an `EFSW` token representing staged writes.

### Security Note

Important

Tokens are not encrypted. Treat tokens as sensitive data:

- Tokens can include unique identifiers (for example MAC/UUID-like fields) and security-relevant configuration bits (secure boot, flash encryption, JTAG/UART disablement, key purposes).

- `EFSW` tokens represent staged writes. They may include write-only key data in plaintext because the staged view shows values that have not yet been burned and are not yet protected by the eFuse read-protection bits. This can disclose provisioning intent and secret material before it is irreversibly locked down.

- `EFSRW` tokens include the same staged portion and therefore carry the same plaintext key-exposure risk.

- Even when certain eFuses are read-protected on the target, the token may still carry operationally sensitive values.

If firmware exposes a console command, remote endpoint, or other runtime API that prints eFuse tokens, the firmware must authenticate and authorize that request before generating the token.

Recommendations:

- Share tokens only with trusted parties and via trusted channels (avoid public issue trackers).

- Store tokens as you would store other manufacturing/provisioning artifacts (restricted access, limited retention).

- Prefer `EFSR` tokens for diagnostics and auditing; use `EFSW` tokens only when you explicitly need to transfer staged write state.

### Token format

A token is a colon-separated sequence:

    <token_name>:<chip>:<ver>:<b64_block0>:...:<b64_blockN>:<b64_cerr>:<b64_crc32>

Fields:

- `token_name` — one of `EFSR`, `EFSW`, or `EFSRW`.

- `chip` — chip name (lowercase, without dashes), for example `esp32c3`.

- `ver` — chip revision as three decimal digits (leading zeros), for example `004`. Constructed from major and minor wafer version fields using the formula `ver = major * 100 + minor`, where the major version occupies the first digit and the minor version occupies the last two digits.

- `b64_block0 ... b64_blockN` — Base64URL-encoded per-block data. Each block is a concatenation of 32-bit words in little-endian byte order. The number of blocks is not explicitly encoded in the format. It is derived from the chip type. The number of blocks can be determined by counting the colon separators (`:`) in the token. Empty blocks are represented as consecutive colons (`::`).

- `b64_cerr` — optional Base64URL-encoded coding-error registers snapshot. It may be empty if there are no errors.

- `b64_crc32` — Base64URL-encoded CRC32 over whole token `"<token_name>:<chip>:<ver>:<b64_block0>:...:<b64_blockN>:<b64_cerr>:"`. CRC32 is stored little-endian and encoded as unpadded Base64URL.

A token can be decoded and interpreted correctly only when it is processed using the same target it was created for. ESP-IDF APIs and `espefuse` validate and rely on the following fields: chip name, chip revision, and block layout, as well as CRC32 integrity. If any of these do not match the target chip, decoding errors or missing fields may occur.

Base64URL uses the same alphabet as Base64 but replaces `+` with `-` and `/` with `_`, and omits padding (`=`).

### Generating Token On-Device

Use `esp_efuse_token_dump()` to create a token in a buffer or print it to the log:

    char token[1024]; /* size depends on target and eFuses */
    esp_efuse_token_type_t token_type = ESP_EFUSE_TOKEN_FROM_READ;
    ESP_ERROR_CHECK(esp_efuse_token_dump(token_type, token, sizeof(token)));
    ESP_LOGI(TAG, "IDF_MONITOR_EXECUTE_ESPEFUSE_SUMMARY %s", token);

Token type values:

- `ESP_EFUSE_TOKEN_FROM_READ` — token of programmed eFuses (starts with `EFSR`).

- `ESP_EFUSE_TOKEN_FROM_STAGED` — token of staged writes (starts with `EFSW`). It can expose keys in plaintext because it shows values that are not yet burned and not yet read-protected. Requires CONFIG_EFUSE_ENABLE_STAGED_TOKEN_API. Only this type can be burned back.

- `ESP_EFUSE_TOKEN_FROM_READ_STAGED` — combined token (starts with `EFSRW`). It includes the same staged portion and the same plaintext key-exposure risk. Requires CONFIG_EFUSE_ENABLE_STAGED_TOKEN_API.

If `buf == NULL`, the token is printed to the console (INFO level) without colors, tag, or timestamp.

### Burn Token On-Device

Use `esp_efuse_token_burn()` to apply an `EFSW` token on the device by burning the staged eFuse writes encoded in the token. The function validates the token integrity (CRC32) and checks compatibility using the chip name and revision. The token is rejected if the major wafer version does not match the target chip. To bypass the version check, use the ignore argument. Example of burning a token:

    esp_efuse_batch_write_begin();
    esp_efuse_token_burn(token, false);  // set true to ignore major version mismatch
    esp_efuse_batch_write_commit();

You can skip the major-version check only when you know the token was generated for the same eFuse layout (for example, the same target with only a minor wafer revision difference); in that case the token version may differ only in the last two digits, while the first digit (major version) must normally match.

### ESP-IDF Monitor Integration

When running `idf.py monitor`, the host can automatically decode eFuse tokens printed by the target and display the result inline if the log line starts with one of the following markers:

- `IDF_MONITOR_EXECUTE_ESPEFUSE_SUMMARY` → `espefuse --token {ARGS} summary --active`

- `IDF_MONITOR_EXECUTE_ESPEFUSE_DUMP` → `espefuse --token <TOKEN> dump`

`{ARGS}` must include an eFuse token (`EFSR/EFSW/EFSRW`) and may include `--extend-efuse-table <csv>` to load custom eFuse definitions.

Example: The following shows executing the summary command with `--active` to display only non-zero eFuse fields, which reduces output size. The `--extend-efuse-table` option loads a custom eFuse table definition:

    I (441) example: IDF_MONITOR_EXECUTE_ESPEFUSE_SUMMARY EFSR:esp32c3:100:AAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAA:zIH3-VVgAAAAAAAAAAAAS8kmEVKwQgYB:ZSd8yloMSAJssOWmfZQw8lFbphuTZH574QcV3ggAAAA:AAAAAAAAAAEayAcAAAAAAAAAAAAAAAAAAAAAAAAAAAA:::::::::ydrNkQ --extend-efuse-table main/esp_efuse_custom_table.csv

     --- Executing monitor command: espefuse --token EFSR:esp32c3:100:AAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAA:zIH3-VVgAAAAAAAAAAAAS8kmEVKwQgYB:ZSd8yloMSAJssOWmfZQw8lFbphuTZH574QcV3ggAAAA:AAAAAAAAAAEayAcAAAAAAAAAAAAAAAAAAAAAAAAAAAA:::::::::ydrNkQ --extend-efuse-table main/esp_efuse_custom_table.csv summary --active
     espefuse v5.1.0

     === Run "summary" command ===
     EFUSE_NAME (Block) Description  = [Meaningful Value] [Readable/Writeable] (Hex Value)
     ----------------------------------------------------------------------------------------
     Calibration fuses:
     K_RTC_LDO (BLOCK1)                                 BLOCK1 K_RTC_LDO                                   = 77 R/W (0b1001101)
     K_DIG_LDO (BLOCK1)                                 BLOCK1 K_DIG_LDO                                   = 68 R/W (0b1000100)
     V_RTC_DBIAS20 (BLOCK1)                             BLOCK1 voltage of rtc dbias20                      = 144 R/W (0x90)
     V_DIG_DBIAS20 (BLOCK1)                             BLOCK1 voltage of digital dbias20                  = 130 R/W (0x82)
     DIG_DBIAS_HVT (BLOCK1)                             BLOCK1 digital dbias when hvt                      = 21 R/W (0b10101)
     THRES_HVT (BLOCK1)                                 BLOCK1 pvt threshold when hvt                      = 400 R/W (0b0110010000)
     TEMP_CALIB (BLOCK2)                                Temperature calibration data                       = -10.600000000000001 R/W (0b101101010)
     OCODE (BLOCK2)                                     ADC OCode                                          = 101 R/W (0x65)
     ADC1_INIT_CODE_ATTEN0 (BLOCK2)                     ADC1 init code at atten0                           = 442 R/W (0b0110111010)
     ADC1_INIT_CODE_ATTEN1 (BLOCK2)                     ADC1 init code at atten1                           = 588 R/W (0b1001001100)
     ADC1_INIT_CODE_ATTEN2 (BLOCK2)                     ADC1 init code at atten2                           = 612 R/W (0b1001100100)
     ADC1_INIT_CODE_ATTEN3 (BLOCK2)                     ADC1 init code at atten3                           = 735 R/W (0b1011011111)
     ADC1_CAL_VOL_ATTEN0 (BLOCK2)                       ADC1 calibration voltage at atten0                 = 535 R/W (0b1000010111)
     ADC1_CAL_VOL_ATTEN1 (BLOCK2)                       ADC1 calibration voltage at atten1                 = 31 R/W (0b0000011111)
     ADC1_CAL_VOL_ATTEN2 (BLOCK2)                       ADC1 calibration voltage at atten2                 = 533 R/W (0b1000010101)
     ADC1_CAL_VOL_ATTEN3 (BLOCK2)                       ADC1 calibration voltage at atten3                 = 567 R/W (0b1000110111)

     Config fuses:
     ERR_RST_ENABLE (BLOCK0)                            Use BLOCK0 to check error record registers         = with check R/W (0b1)
     BLOCK_USR_DATA (BLOCK3)                            User data
     = 00 00 00 00 00 00 00 01 1a c8 07 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W

     Flash fuses:
     FLASH_CAP (BLOCK1)                                 Flash capacity                                     = 4M R/W (0b001)
     FLASH_TEMP (BLOCK1)                                Flash temperature                                  = 105C R/W (0b01)
     FLASH_VENDOR (BLOCK1)                              Flash vendor                                       = XMC R/W (0b001)

     Identity fuses:
     BLK_VERSION_MINOR (BLOCK1)                         BLK_VERSION_MINOR                                  = 3 R/W (0b011)
     WAFER_VERSION_MAJOR (BLOCK1)                       WAFER_VERSION_MAJOR                                = 1 R/W (0b01)
     OPTIONAL_UNIQUE_ID (BLOCK2)                        Optional unique 128-bit ID
     = 65 27 7c ca 5a 0c 48 02 6c b0 e5 a6 7d 94 30 f2 R/W
     BLK_VERSION_MAJOR (BLOCK2)                         BLK_VERSION_MAJOR of BLOCK2                        = With calibration R/W (0b01)

     Mac fuses:
     MAC (BLOCK1)                                       MAC address
     = 60:55:f9:f7:81:cc (OK) R/W

     User fuses:
     MODULE_VERSION (BLOCK3)                            Module version (56-63)                             = 1 R/W (0x01)
     DEVICE_ROLE (BLOCK3)                               Device role (64-66)                                = 2 R/W (0b010)
     SETTING_1 (BLOCK3)                                 Setting 1 (67-72)                                  = 3 R/W (0b000011)
     SETTING_2 (BLOCK3)                                 Setting 2 (73-77)                                  = 4 R/W (0b00100)
     CUSTOM_SECURE_VERSION (BLOCK3)                     Custom secure version (78-93)                      = 31 R/W (0x001f)
     ...

Example (dump):

    I (441) example: IDF_MONITOR_EXECUTE_ESPEFUSE_DUMP EFSR:esp32c3:100:AAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAA:zIH3-VVgAAAAAAAAAAAAS8kmEVKwQgYB:ZSd8yloMSAJssOWmfZQw8lFbphuTZH574QcV3ggAAAA:AAAAAAAAAAEayAcAAAAAAAAAAAAAAAAAAAAAAAAAAAA:::::::::ydrNkQ

    --- Executing monitor command: espefuse --token EFSR:esp32c3:100:AAAAAAAAAAAAAAAAAAAAAAAAAIAAAAAA:zIH3-VVgAAAAAAAAAAAAS8kmEVKwQgYB:ZSd8yloMSAJssOWmfZQw8lFbphuTZH574QcV3ggAAAA:AAAAAAAAAAEayAcAAAAAAAAAAAAAAAAAAAAAAAAAAAA:::::::::ydrNkQ dump
    espefuse v5.1.0

    === Run "dump" command ===
    BLOCK0          (                ) [0 ] dump: 00000000 00000000 00000000 00000000 80000000 00000000
    MAC_SPI_8M_0    (BLOCK1          ) [1 ] dump: f9f781cc 00006055 00000000 4b000000 521126c9 010642b0
    BLOCK_SYS_DATA  (BLOCK2          ) [2 ] dump: ca7c2765 02480c5a a6e5b06c f230947d 1ba65b51 7b7e6493 de1507e1 00000008
    BLOCK_USR_DATA  (BLOCK3          ) [3 ] dump: 00000000 01000000 0007c81a 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY0      (BLOCK4          ) [4 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY1      (BLOCK5          ) [5 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY2      (BLOCK6          ) [6 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY3      (BLOCK7          ) [7 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY4      (BLOCK8          ) [8 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_KEY5      (BLOCK9          ) [9 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    BLOCK_SYS_DATA2 (BLOCK10         ) [10] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

## Application Examples

- system/efuse demonstrates how to use the eFuse API on ESP32-H4, showing read and write operations with fields from the common and custom eFuse tables, and explaining the use of virtual eFuses for debugging purposes.

## API Reference

### Header File

- components/efuse/esp32h4/include/esp_efuse_chip.h

- This header file can be included with:

  >     #include "esp_efuse_chip.h"

- This header file is a part of the API provided by the `efuse` component. To declare that your component depends on `efuse`, add the following to your CMakeLists.txt:

  >     REQUIRES efuse

  > or

  >     PRIV_REQUIRES efuse

### Enumerations

enum esp_efuse_block_t

  Type of eFuse blocks ESP32H4.

  Values:

  enumerator EFUSE_BLK0

    Number of eFuse BLOCK0. REPEAT_DATA

  enumerator EFUSE_BLK1

    Number of eFuse BLOCK1. MAC_SPI_8M_SYS

  enumerator EFUSE_BLK2

    Number of eFuse BLOCK2. SYS_DATA_PART1

  enumerator EFUSE_BLK_SYS_DATA_PART1

    Number of eFuse BLOCK2. SYS_DATA_PART1

  enumerator EFUSE_BLK3

    Number of eFuse BLOCK3. USER_DATA

  enumerator EFUSE_BLK_USER_DATA

    Number of eFuse BLOCK3. USER_DATA

  enumerator EFUSE_BLK4

    Number of eFuse BLOCK4. KEY0

  enumerator EFUSE_BLK_KEY0

    Number of eFuse BLOCK4. KEY0

  enumerator EFUSE_BLK5

    Number of eFuse BLOCK5. KEY1

  enumerator EFUSE_BLK_KEY1

    Number of eFuse BLOCK5. KEY1

  enumerator EFUSE_BLK6

    Number of eFuse BLOCK6. KEY2

  enumerator EFUSE_BLK_KEY2

    Number of eFuse BLOCK6. KEY2

  enumerator EFUSE_BLK7

    Number of eFuse BLOCK7. KEY3

  enumerator EFUSE_BLK_KEY3

    Number of eFuse BLOCK7. KEY3

  enumerator EFUSE_BLK8

    Number of eFuse BLOCK8. KEY4

  enumerator EFUSE_BLK_KEY4

    Number of eFuse BLOCK8. KEY4

  enumerator EFUSE_BLK9

    Number of eFuse BLOCK9. KEY5

  enumerator EFUSE_BLK_KEY5

    Number of eFuse BLOCK9. KEY5

  enumerator EFUSE_BLK_KEY_MAX
  enumerator EFUSE_BLK10

    Number of eFuse BLOCK10. SYS_DATA_PART2

  enumerator EFUSE_BLK_SYS_DATA_PART2

    Number of eFuse BLOCK10. SYS_DATA_PART2

  enumerator EFUSE_BLK_MAX

enum esp_efuse_coding_scheme_t

  Type of coding scheme.

  Values:

  enumerator EFUSE_CODING_SCHEME_NONE

    None

  enumerator EFUSE_CODING_SCHEME_RS

    Reed-Solomon coding

enum esp_efuse_purpose_t

  Type of key purpose.

  Values:

  enumerator ESP_EFUSE_KEY_PURPOSE_USER

    User purposes (software-only use)

  enumerator ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY

    ECDSA private key (P256) (Expected in little endian order)

  enumerator ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY_P256

    ECDSA private key (P256) (Expected in little endian order)

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_256_KEY_1

    Flash encryption key (XTS_AES_256_KEY_1)

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_256_KEY_2

    Flash encryption key (XTS_AES_256_KEY_2)

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_128_KEY

    XTS_AES_128_KEY (flash/PSRAM encryption)

  enumerator ESP_EFUSE_KEY_PURPOSE_HMAC_DOWN_ALL

    HMAC Downstream mode

  enumerator ESP_EFUSE_KEY_PURPOSE_HMAC_DOWN_JTAG

    JTAG soft enable key (uses HMAC Downstream mode)

  enumerator ESP_EFUSE_KEY_PURPOSE_HMAC_DOWN_DIGITAL_SIGNATURE

    Keep for compatibility although H4 has no DS peripheral

  enumerator ESP_EFUSE_KEY_PURPOSE_HMAC_UP

    HMAC Upstream mode

  enumerator ESP_EFUSE_KEY_PURPOSE_SECURE_BOOT_DIGEST0

    SECURE_BOOT_DIGEST0 (Secure Boot key digest)

  enumerator ESP_EFUSE_KEY_PURPOSE_SECURE_BOOT_DIGEST1

    SECURE_BOOT_DIGEST1 (Secure Boot key digest)

  enumerator ESP_EFUSE_KEY_PURPOSE_SECURE_BOOT_DIGEST2

    SECURE_BOOT_DIGEST2 (Secure Boot key digest)

  enumerator ESP_EFUSE_KEY_PURPOSE_KM_INIT_KEY

    KM_INIT_KEY

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_256_PSRAM_KEY_1

    PSRAM encryption key (XTS_AES_256_KEY_1)

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_256_PSRAM_KEY_2

    PSRAM encryption key (XTS_AES_256_KEY_2)

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_128_PSRAM_KEY

    PSRAM encryption key (XTS_AES_128_KEY)

  enumerator ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY_P192

    ECDSA private key (P192)

  enumerator ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY_P384_L

    ECDSA private key (P384 low)

  enumerator ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY_P384_H

    ECDSA private key (P384 high)

  enumerator ESP_EFUSE_KEY_PURPOSE_MAX

    MAX PURPOSE

### Header File

- components/efuse/include/esp_efuse.h

- This header file can be included with:

  >     #include "esp_efuse.h"

- This header file is a part of the API provided by the `efuse` component. To declare that your component depends on `efuse`, add the following to your CMakeLists.txt:

  >     REQUIRES efuse

  > or

  >     PRIV_REQUIRES efuse

### Functions

esp_err_t esp_efuse_read_field_blob(const esp_efuse_desc_t *field[], void *dst, size_t dst_size_bits)

  Reads bits from EFUSE field and writes it into an array.

  The number of read bits will be limited to the minimum value from the description of the bits in "field" structure or "dst_size_bits" required size. Use "esp_efuse_get_field_size()" function to determine the length of the field.

  Note

  Please note that reading in the batch mode does not show uncommitted changes.

  Parameters:

    - field -- [in] A pointer to the structure describing the fields of efuse.

    - dst -- [out] A pointer to array that will contain the result of reading.

    - dst_size_bits -- [in] The number of bits required to read. If the requested number of bits is greater than the field, the number will be limited to the field size.

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

bool esp_efuse_read_field_bit(const esp_efuse_desc_t *field[])

  Read a single bit eFuse field as a boolean value.

  Note

  The value must exist and must be a single bit wide. If there is any possibility of an error in the provided arguments, call esp_efuse_read_field_blob() and check the returned value instead.

  Note

  If assertions are enabled and the parameter is invalid, execution will abort

  Note

  Please note that reading in the batch mode does not show uncommitted changes.

  Parameters:

    field -- [in] A pointer to the structure describing the fields of efuse.

  Returns:

    - true: The field parameter is valid and the bit is set.

    - false: The bit is not set, or the parameter is invalid and assertions are disabled.

esp_err_t esp_efuse_read_field_cnt(const esp_efuse_desc_t *field[], size_t *out_cnt)

  Reads bits from EFUSE field and returns number of bits programmed as "1".

  If the bits are set not sequentially, they will still be counted.

  Note

  Please note that reading in the batch mode does not show uncommitted changes.

  Parameters:

    - field -- [in] A pointer to the structure describing the fields of efuse.

    - out_cnt -- [out] A pointer that will contain the number of programmed as "1" bits.

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

esp_err_t esp_efuse_write_field_blob(const esp_efuse_desc_t *field[], const void *src, size_t src_size_bits)

  Writes array to EFUSE field.

  The number of write bits will be limited to the minimum value from the description of the bits in "field" structure or "src_size_bits" required size. Use "esp_efuse_get_field_size()" function to determine the length of the field. After the function is completed, the writing registers are cleared.

  Parameters:

    - field -- [in] A pointer to the structure describing the fields of efuse.

    - src -- [in] A pointer to array that contains the data for writing.

    - src_size_bits -- [in] The number of bits required to write.

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

esp_err_t esp_efuse_write_field_cnt(const esp_efuse_desc_t *field[], size_t cnt)

  Writes a required count of bits as "1" to EFUSE field.

  If there are no free bits in the field to set the required number of bits to "1", ESP_ERR_EFUSE_CNT_IS_FULL error is returned, the field will not be partially recorded. After the function is completed, the writing registers are cleared.

  Parameters:

    - field -- [in] A pointer to the structure describing the fields of efuse.

    - cnt -- [in] Required number of programmed as "1" bits.

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_CNT_IS_FULL: Not all requested cnt bits is set.

esp_err_t esp_efuse_write_field_bit(const esp_efuse_desc_t *field[])

  Write a single bit eFuse field to 1.

  For use with eFuse fields that are a single bit. This function will write the bit to value 1 if it is not already set, or does nothing if the bit is already set.

  This is equivalent to calling esp_efuse_write_field_cnt() with the cnt parameter equal to 1, except that it will return ESP_OK if the field is already set to 1.

  Parameters:

    field -- [in] Pointer to the structure describing the efuse field.

  Returns:

    - ESP_OK: The operation was successfully completed, or the bit was already set to value 1.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments, including if the efuse field is not 1 bit wide.

esp_err_t esp_efuse_set_write_protect(esp_efuse_block_t blk)

  Sets a write protection for the whole block.

  After that, it is impossible to write to this block. The write protection does not apply to block 0.

  Parameters:

    blk -- [in] Block number of eFuse. (EFUSE_BLK1, EFUSE_BLK2 and EFUSE_BLK3)

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_CNT_IS_FULL: Not all requested cnt bits is set.

    - ESP_ERR_NOT_SUPPORTED: The block does not support this command.

    - ESP_ERR_BURN_WR_DIS: Failed to burn WR_DIS field.

esp_err_t esp_efuse_set_read_protect(esp_efuse_block_t blk)

  Sets a read protection for the whole block.

  After that, it is impossible to read from this block. The read protection does not apply to block 0.

  Parameters:

    blk -- [in] Block number of eFuse. (EFUSE_BLK1, EFUSE_BLK2 and EFUSE_BLK3)

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_CNT_IS_FULL: Not all requested cnt bits is set.

    - ESP_ERR_NOT_SUPPORTED: The block does not support this command.

int esp_efuse_get_field_size(const esp_efuse_desc_t *field[])

  Returns the number of bits used by field.

  Parameters:

    field -- [in] A pointer to the structure describing the fields of efuse.

  Returns:

    Returns the number of bits used by field.

uint32_t esp_efuse_read_reg(esp_efuse_block_t blk, unsigned int num_reg)

  Returns value of efuse register.

  This is a thread-safe implementation. Example: EFUSE_BLK2_RDATA3_REG where (blk=2, num_reg=3)

  Note

  Please note that reading in the batch mode does not show uncommitted changes.

  Parameters:

    - blk -- [in] Block number of eFuse.

    - num_reg -- [in] The register number in the block.

  Returns:

    Value of register

esp_err_t esp_efuse_write_reg(esp_efuse_block_t blk, unsigned int num_reg, uint32_t val)

  Write value to efuse register.

  Apply a coding scheme if necessary. This is a thread-safe implementation. Example: EFUSE_BLK3_WDATA0_REG where (blk=3, num_reg=0)

  Parameters:

    - blk -- [in] Block number of eFuse.

    - num_reg -- [in] The register number in the block.

    - val -- [in] Value to write.

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

esp_efuse_coding_scheme_t esp_efuse_get_coding_scheme(esp_efuse_block_t blk)

  Return efuse coding scheme for blocks.

  Note

  The coding scheme is applicable only to 1, 2 and 3 blocks. For 0 block, the coding scheme is always `NONE`.

  Parameters:

    blk -- [in] Block number of eFuse.

  Returns:

    Return efuse coding scheme for blocks

esp_err_t esp_efuse_read_block(esp_efuse_block_t blk, void *dst_key, size_t offset_in_bits, size_t size_bits)

  Read key to efuse block starting at the offset and the required size.

  Note

  Please note that reading in the batch mode does not show uncommitted changes.

  Parameters:

    - blk -- [in] Block number of eFuse.

    - dst_key -- [in] A pointer to array that will contain the result of reading.

    - offset_in_bits -- [in] Start bit in block.

    - size_bits -- [in] The number of bits required to read.

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

esp_err_t esp_efuse_write_block(esp_efuse_block_t blk, const void *src_key, size_t offset_in_bits, size_t size_bits)

  Write key to efuse block starting at the offset and the required size.

  Parameters:

    - blk -- [in] Block number of eFuse.

    - src_key -- [in] A pointer to array that contains the key for writing.

    - offset_in_bits -- [in] Start bit in block.

    - size_bits -- [in] The number of bits required to write.

  Returns:

    - ESP_OK: The operation was successfully completed.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits

uint32_t esp_efuse_get_pkg_ver(void)

  Returns chip package from efuse.

  Returns:

    chip package

esp_err_t esp_efuse_set_recovery_bootloader_offset(const uint32_t offset)

  Sets the recovery bootloader flash offset in eFuse.

  This function is used to set the flash offset in eFuse for the recovery bootloader. If an offset is already set in eFuse, it will be validated against the provided offset.

  Parameters:

    offset -- Flash offset where the recovery bootloader is located.

  Returns:

    - ESP_OK: Successfully set or given offset is already set.

    - ESP_ERR_NOT_ALLOWED: Recovery bootloader feature is disabled in eFuse.

    - ESP_FAIL: Failed to update the recovery bootloader flash offset.

    - Error code from eFuse read/write operations if an error occurs.

void esp_efuse_reset(void)

  Reset efuse write registers.

  Efuse write registers are written to zero, to negate any changes that have been staged here.

  Note

  This function is not threadsafe, if calling code updates efuse values from multiple tasks then this is caller's responsibility to serialise.

esp_err_t esp_efuse_disable_rom_download_mode(void)

  Disable ROM Download Mode via eFuse.

  Permanently disables the ROM Download Mode feature. Once disabled, if the SoC is booted with strapping pins set for ROM Download Mode then an error is printed instead.

  Note

  Not all SoCs support this option. An error will be returned if called on an ESP32 with a silicon revision lower than 3, as these revisions do not support this option.

  Note

  If ROM Download Mode is already disabled, this function does nothing and returns success.

  Returns:

    - ESP_OK If the eFuse was successfully burned, or had already been burned.

    - ESP_ERR_NOT_SUPPORTED (ESP32 only) This SoC is not capable of disabling UART download mode

    - ESP_ERR_INVALID_STATE (ESP32 only) This eFuse is write protected and cannot be written

esp_err_t esp_efuse_set_rom_log_scheme(esp_efuse_rom_log_scheme_t log_scheme)

  Set boot ROM log scheme via eFuse.

  Note

  By default, the boot ROM will always print to console. This API can be called to set the log scheme only once per chip, once the value is changed from the default it can't be changed again.

  Parameters:

    log_scheme -- Supported ROM log scheme

  Returns:

    - ESP_OK If the eFuse was successfully burned, or had already been burned.

    - ESP_ERR_NOT_SUPPORTED (ESP32 only) This SoC is not capable of setting ROM log scheme

    - ESP_ERR_INVALID_STATE This eFuse is write protected or has been burned already

uint32_t esp_efuse_read_secure_version(void)

  Return secure_version from efuse field.

  Returns:

    Secure version from efuse field

bool esp_efuse_check_secure_version(uint32_t secure_version)

  Check secure_version from app and secure_version and from efuse field.

  Parameters:

    secure_version -- Secure version from app.

  Returns:

    - True: If version of app is equal or more then secure_version from efuse.

esp_err_t esp_efuse_update_secure_version(uint32_t secure_version)

  Write efuse field by secure_version value.

  Update the secure_version value is available if the coding scheme is None. Note: Do not use this function in your applications. This function is called as part of the other API.

  Parameters:

    secure_version -- [in] Secure version from app.

  Returns:

    - ESP_OK: Successful.

    - ESP_FAIL: secure version of app cannot be set to efuse field.

    - ESP_ERR_NOT_SUPPORTED: Anti rollback is not supported with the 3/4 and Repeat coding scheme.

esp_err_t esp_efuse_batch_write_begin(void)

  Set the batch mode of writing fields.

  This mode allows you to write the fields in the batch mode when need to burn several efuses at one time. To enable batch mode call begin() then perform as usually the necessary operations read and write and at the end call commit() to actually burn all written efuses. The batch mode can be used nested. The commit will be done by the last commit() function. The number of begin() functions should be equal to the number of commit() functions.

  Note: If batch mode is enabled by the first task, at this time the second task cannot write/read efuses. The second task will wait for the first task to complete the batch operation.

      // Example of using the batch writing mode.

      // set the batch writing mode
      esp_efuse_batch_write_begin();

      // use any writing functions as usual
      esp_efuse_write_field_blob(ESP_EFUSE_...);
      esp_efuse_write_field_cnt(ESP_EFUSE_...);
      esp_efuse_set_write_protect(EFUSE_BLKx);
      esp_efuse_write_reg(EFUSE_BLKx, ...);
      esp_efuse_write_block(EFUSE_BLKx, ...);
      esp_efuse_write(ESP_EFUSE_1, 3);  // ESP_EFUSE_1 == 1, here we write a new value = 3. The changes will be burn by the commit() function.
      esp_efuse_read_...(ESP_EFUSE_1);  // this function returns ESP_EFUSE_1 == 1 because uncommitted changes are not readable, it will be available only after commit.
      ...

      // esp_efuse_batch_write APIs can be called recursively.
      esp_efuse_batch_write_begin();
      esp_efuse_set_write_protect(EFUSE_BLKx);
      esp_efuse_batch_write_commit(); // the burn will be skipped here, it will be done in the last commit().

      ...

      // Write all of these fields to the efuse registers
      esp_efuse_batch_write_commit();
      esp_efuse_read_...(ESP_EFUSE_1);  // this function returns ESP_EFUSE_1 == 3.

  Note

  Please note that reading in the batch mode does not show uncommitted changes.

  Returns:

    - ESP_OK: Successful.

esp_err_t esp_efuse_batch_write_cancel(void)

  Reset the batch mode of writing fields.

  It will reset the batch writing mode and any written changes.

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_STATE: The batch mode was not set.

esp_err_t esp_efuse_batch_write_commit(void)

  Writes all prepared data for the batch mode.

  Must be called to ensure changes are written to the efuse registers. After this the batch writing mode will be reset.

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_STATE: The deferred writing mode was not set.

    - ESP_FAIL: Failed to write efuse fields.

    - ESP_ERR_BURN_WR_DIS: Failed to burn WR_DIS field.

bool esp_efuse_block_is_empty(esp_efuse_block_t block)

  Checks that the given block is empty.

  Returns:

    - True: The block is empty.

    - False: The block is not empty or was an error.

bool esp_efuse_get_key_dis_read(esp_efuse_block_t block)

  Returns a read protection for the key block.

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    True: The key block is read protected False: The key block is readable.

esp_err_t esp_efuse_set_key_dis_read(esp_efuse_block_t block)

  Sets a read protection for the key block.

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

bool esp_efuse_get_key_dis_write(esp_efuse_block_t block)

  Returns a write protection for the key block.

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    True: The key block is write protected False: The key block is writeable.

esp_err_t esp_efuse_set_key_dis_write(esp_efuse_block_t block)

  Sets a write protection for the key block.

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

    - ESP_ERR_BURN_WR_DIS: Failed to burn WR_DIS field.

bool esp_efuse_key_block_unused(esp_efuse_block_t block)

  Returns true if the key block is unused, false otherwise.

  An unused key block is all zero content, not read or write protected, and has purpose 0 (ESP_EFUSE_KEY_PURPOSE_USER)

  Parameters:

    block -- key block to check.

  Returns:

    - True if key block is unused,

    - False if key block is used or the specified block index is not a key block.

bool esp_efuse_find_purpose(esp_efuse_purpose_t purpose, esp_efuse_block_t *block)

  Find a key block with the particular purpose set.

  Parameters:

    - purpose -- [in] Purpose to search for.

    - block -- [out] Pointer in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX which will be set to the key block if found. Can be NULL, if only need to test the key block exists.

  Returns:

    - True: If found,

    - False: If not found (value at block pointer is unchanged).

bool esp_efuse_get_keypurpose_dis_write(esp_efuse_block_t block)

  Returns a write protection of the key purpose field for an efuse key block.

  Note

  For ESP32: no keypurpose, it returns always True.

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    True: The key purpose is write protected. False: The key purpose is writeable.

esp_efuse_purpose_t esp_efuse_get_key_purpose(esp_efuse_block_t block)

  Returns the current purpose set for an efuse key block.

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    - Value: If Successful, it returns the value of the purpose related to the given key block.

    - ESP_EFUSE_KEY_PURPOSE_MAX: Otherwise.

const esp_efuse_desc_t **esp_efuse_get_purpose_field(esp_efuse_block_t block)

  Returns a pointer to a key purpose for an efuse key block.

  To get the value of this field use esp_efuse_read_field_blob() or esp_efuse_get_key_purpose().

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    Pointer: If Successful returns a pointer to the corresponding efuse field otherwise NULL.

const esp_efuse_desc_t **esp_efuse_get_key(esp_efuse_block_t block)

  Returns a pointer to a key block.

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    Pointer: If Successful returns a pointer to the corresponding efuse field otherwise NULL.

esp_err_t esp_efuse_set_key_purpose(esp_efuse_block_t block, esp_efuse_purpose_t purpose)

  Sets a key purpose for an efuse key block.

  Parameters:

    - block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

    - purpose -- [in] Key purpose.

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

esp_err_t esp_efuse_set_keypurpose_dis_write(esp_efuse_block_t block)

  Sets a write protection of the key purpose field for an efuse key block.

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

    - ESP_ERR_BURN_WR_DIS: Failed to burn WR_DIS field.

esp_efuse_block_t esp_efuse_find_unused_key_block(void)

  Search for an unused key block and return the first one found.

  See esp_efuse_key_block_unused for a description of an unused key block.

  Returns:

    First unused key block, or EFUSE_BLK_KEY_MAX if no unused key block is found.

unsigned esp_efuse_count_unused_key_blocks(void)

  Return the number of unused efuse key blocks in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX.

bool esp_efuse_get_digest_revoke(unsigned num_digest)

  Returns the status of the Secure Boot public key digest revocation bit.

  Parameters:

    num_digest -- [in] The number of digest in range 0..2

  Returns:

    - True: If key digest is revoked,

    - False; If key digest is not revoked.

esp_err_t esp_efuse_set_digest_revoke(unsigned num_digest)

  Sets the Secure Boot public key digest revocation bit.

  Parameters:

    num_digest -- [in] The number of digest in range 0..2

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

bool esp_efuse_get_write_protect_of_digest_revoke(unsigned num_digest)

  Returns a write protection of the Secure Boot public key digest revocation bit.

  Parameters:

    num_digest -- [in] The number of digest in range 0..2

  Returns:

    True: The revocation bit is write protected. False: The revocation bit is writeable.

esp_err_t esp_efuse_set_write_protect_of_digest_revoke(unsigned num_digest)

  Sets a write protection of the Secure Boot public key digest revocation bit.

  Parameters:

    num_digest -- [in] The number of digest in range 0..2

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

    - ESP_ERR_BURN_WR_DIS: Failed to burn WR_DIS field.

esp_err_t esp_efuse_write_key(esp_efuse_block_t block, esp_efuse_purpose_t purpose, const void *key, size_t key_size_bytes)

  Program a block of key data to an efuse block.

  The burn of a key, protection bits, and a purpose happens in batch mode.

  Note

  This API also enables the read protection efuse bit for certain key blocks like XTS-AES, HMAC, ECDSA etc. This ensures that the key is only accessible to hardware peripheral.

  Note

  For SoC's with capability `SOC_EFUSE_ECDSA_USE_HARDWARE_K` (e.g., ESP32-H2), this API writes an additional efuse bit for ECDSA key purpose to enforce hardware TRNG generated k mode in the peripheral.

  Parameters:

    - block -- [in] Block to read purpose for. Must be in range EFUSE_BLK_KEY0 to EFUSE_BLK_KEY_MAX. Key block must be unused (esp_efuse_key_block_unused).

    - purpose -- [in] Purpose to set for this key. Purpose must be already unset.

    - key -- [in] Pointer to data to write.

    - key_size_bytes -- [in] Bytes length of data to write.

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_INVALID_STATE: Error in efuses state, unused block not found.

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

    - ESP_ERR_BURN_WR_DIS: Failed to burn WR_DIS field.

esp_err_t esp_efuse_write_keys(const esp_efuse_purpose_t purposes[], uint8_t keys[][32], unsigned number_of_keys)

  Program keys to unused efuse blocks.

  The burn of keys, protection bits, and purposes happens in batch mode.

  Note

  This API also enables the read protection efuse bit for certain key blocks like XTS-AES, HMAC, ECDSA etc. This ensures that the key is only accessible to hardware peripheral.

  Note

  For SoC's with capability `SOC_EFUSE_ECDSA_USE_HARDWARE_K` (e.g., ESP32-H2), this API writes an additional efuse bit for ECDSA key purpose to enforce hardware TRNG generated k mode in the peripheral.

  Parameters:

    - purposes -- [in] Array of purposes (purpose[number_of_keys]).

    - keys -- [in] Array of keys (uint8_t keys[number_of_keys][32]). Each key is 32 bytes long.

    - number_of_keys -- [in] The number of keys to write (up to 6 keys).

  Returns:

    - ESP_OK: Successful.

    - ESP_ERR_INVALID_ARG: Error in the passed arguments.

    - ESP_ERR_INVALID_STATE: Error in efuses state, unused block not found.

    - ESP_ERR_NOT_ENOUGH_UNUSED_KEY_BLOCKS: Error not enough unused key blocks available

    - ESP_ERR_EFUSE_REPEATED_PROG: Error repeated programming of programmed bits is strictly forbidden.

    - ESP_ERR_CODING: Error range of data does not match the coding scheme.

    - ESP_ERR_BURN_WR_DIS: Failed to burn WR_DIS field.

esp_err_t esp_secure_boot_read_key_digests(esp_secure_boot_key_digests_t *trusted_key_digests)

  Read key digests from efuse. Any revoked/missing digests will be marked as NULL.

  Parameters:

    trusted_key_digests -- [out] Trusted keys digests, stored in this parameter after successfully completing this function. The number of digests depends on the SOC's capabilities.

  Returns:

    - ESP_OK: Successful.

    - ESP_FAIL: If trusted_keys is NULL or there is no valid digest.

esp_err_t esp_efuse_check_errors(void)

  Checks eFuse errors in BLOCK0.

  It does a BLOCK0 check if eFuse EFUSE_ERR_RST_ENABLE is set. If BLOCK0 has an error, it prints the error and returns ESP_FAIL, which should be treated as esp_restart.

  Note

  Refers to ESP32-C3 only.

  Returns:

    - ESP_OK: No errors in BLOCK0.

    - ESP_FAIL: Error in BLOCK0 requiring reboot.

esp_err_t esp_efuse_destroy_block(esp_efuse_block_t block)

  Destroys the data in the given efuse block, if possible.

  Data destruction occurs through the following steps: 1) Destroy data in the block:

  - If write protection is inactive for the block, then unset bits are burned.

  - If write protection is active, the block remains unaltered. 2) Set read protection for the block if possible (check write-protection for RD_DIS). In this case, data becomes inaccessible, and the software reads it as all zeros. If write protection is enabled and read protection can not be set, data in the block remains readable (returns an error).

  Do not use the batch mode with this function as it does the burning itself!

  Parameters:

    block -- [in] A key block in the range EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX

  Returns:

    - ESP_OK: Successful.

    - ESP_FAIL: Data remained readable because the block is write-protected and read protection can not be set.

bool esp_efuse_is_flash_encryption_enabled(void)

  Checks if flash encryption is enabled.

  This function checks if the current eFuse configuration supports flash encryption.

bool esp_efuse_is_ecdsa_p192_curve_supported(void)

  Checks if 192-bit ECDSA curve operations are supported.

  This function checks if the current eFuse configuration supports 192-bit ECDSA curve operations.

bool esp_efuse_is_ecdsa_p256_curve_supported(void)

  Checks if 256-bit ECDSA curve operations are supported.

  This function checks if the current eFuse configuration supports 256-bit ECDSA curve operations.

esp_err_t esp_efuse_token_dump(esp_efuse_token_type_t dump_type, char *buf, size_t buf_len)

  Print a single-line dump token that serializes all eFuse blocks.

  Token formats (null-terminated strings):

  - Read efuse area EFSR:chip_name:chip_version:b64_blocks:b64_cerr:b64_crc32

  - Staged efuse area EFSW:chip_name:chip_version:b64_blocks:b64_cerr:b64_crc32

  - Combination of two areas (read and staged) EFSRW:...

  This token is useful when a host tool cannot read the device directly (for example, when UART download mode is disabled, secure download is enabled). Copy the entire token string and decode it on a host that has access to espefuse.

  Example (decode token and show only active fields):

      espefuse --token EFSR:esp32:300:AAABAAAAAAAAAAAAAIAAAAAAAAAAABAAAAAAAA::oKGio6SlpqeoqaqrrK2ur7CxsrO0tba3uLm6u7y9vr8:::fPaC-A summary --active

  Where:

  - token_marker = EFSR, EFSW, or EFSRW

  - chip_name = CONFIG_IDF_TARGET (e.g., "esp32c5")

  - chip_version = chip version (e.g., "100" for v1.0). version = major wafer version * 100 + minor wafer version.

  - b64_blocks = concatenation of all blocks’ 32-bit words (little-endian byte order), encoded as Base64URL without padding, for BLK0..BLK_MAX-1.

  - b64_cerr = optional coding-error snapshot.

  - b64_crc32 = crc32("token_marker:chip:ver:b64_blocks:b64_cerr:") b64 - base 64 format (Base64URL, UNPADDED)

  Note

  Dump modes that include staged data (ESP_EFUSE_TOKEN_FROM_STAGED and ESP_EFUSE_TOKEN_FROM_READ_STAGED) can expose sensitive data, including plaintext key material, because they show values before they are burned and before read-protection is applied. Treat EFSW/EFSRW tokens as sensitive artifacts and enable them only with CONFIG_EFUSE_ENABLE_STAGED_TOKEN_API.

  Note

  When `buf` is NULL, the token is printed with esp_log() using a non-constrained logging configuration. If the token must be emitted from a constrained environment, pass a buffer to this function and print or transport the resulting token with a constrained-safe method.

  Parameters:

    - dump_type -- Select which efuse data to dump: read, staged writes, or both.

    - buf -- Buffer to store the resulting token string. If NULL, output goes to console.

    - buf_len -- Length of the buffer. Must be at least ESP_EFUSE_TOKEN_DUMP_MIN_LEN bytes to hold the full token for esp32xx series.

  Returns:

    - ESP_OK on success.

    - ESP_ERR_NOT_SUPPORTED if `dump_type` requests staged data and CONFIG_EFUSE_ENABLE_STAGED_TOKEN_API is disabled to avoid exposing staged values, including plaintext key material, before burn/read-protect.

    - ESP_ERR_INVALID_ARG if `dump_type` is invalid.

    - ESP_ERR_INVALID_SIZE if buf_len is too small

esp_err_t esp_efuse_token_burn(const char *token_in, bool ignore_ver)

  Burns the EFSW token dump.

  EFSW:chip_name:chip_version:b64_blocks::b64_crc32

  The function validates:

  - Token marker EFSW

  - Chip name (must match CONFIG_IDF_TARGET)

  - Chip version is validated unless ignore_ver is set to true. The major version must be equal.

  - Chip version unless ignore_ver is true

  - CRC32

  Note

  The EFSW token dump can be produced from a host or from-device utility. Examples:

  - Host: `espefuse burn-bit BLOCK2 1 --show-token`

  - Device: `esp_efuse_token_dump(ESP_EFUSE_TOKEN_FROM_STAGED, buf, len)`

  Parameters:

    - token_in -- Null-terminated EFSW token string.

    - ignore_ver -- If true, skip enforcing the wafer chip version in the token.

  Returns:

    - ESP_OK on success (token parsed and write efuse area is populated).

    - ESP_ERR_INVALID_ARG on format/mismatch errors (bad token marker/chip/ver/layout)

    - ESP_ERR_INVALID_CRC if CRC verification fails

    - ESP_ERR_INVALID_VERSION if chip version mismatches and ignore_ver is false

    - Other esp_err_t from lower layers if writing/burning fails

### Structures

struct esp_efuse_desc_t

  Type definition for an eFuse field.

  Public Members

  esp_efuse_block_t efuse_block

    Block of eFuse

  uint16_t bit_start

    Start bit [0..511]

  uint16_t bit_count

    Length of bit field [1..-]

struct esp_secure_boot_key_digests_t

  Pointers to the trusted key digests.

  The number of digests depends on the SOC's capabilities.

  Public Members

  const void *key_digests[3]

    Pointers to the key digests

### Macros

ESP_ERR_EFUSE

  Base error code for efuse api.

ESP_OK_EFUSE_CNT

  OK the required number of bits is set.

ESP_ERR_EFUSE_CNT_IS_FULL

  Error field is full.

ESP_ERR_EFUSE_REPEATED_PROG

  Error repeated programming of programmed bits is strictly forbidden.

ESP_ERR_CODING

  Error while a encoding operation.

ESP_ERR_NOT_ENOUGH_UNUSED_KEY_BLOCKS

  Error not enough unused key blocks available

ESP_ERR_DAMAGED_READING

  Error. Burn or reset was done during a reading operation leads to damage read data. This error is internal to the efuse component and not returned by any public API.

ESP_ERR_BURN_WR_DIS

  Error to burn WR_DIS field.

ESP_EFUSE_MONITOR_EXECUTE_ESPEFUSE_SUMMARY

  Flags specifying which source(s) to use when dumping eFUSE data.

  Prefix used in device log lines to trigger automatic token decoding in idf.py monitor.

ESP_EFUSE_MONITOR_EXECUTE_ESPEFUSE_DUMP

  Prefix used in device log lines to trigger token dump decoding in idf.py monitor.

ESP_EFUSE_TOKEN_DUMP_MIN_LEN

  Recommended minimum buffer length for esp_efuse_token_dump().

### Enumerations

enum esp_efuse_rom_log_scheme_t

  Type definition for ROM log scheme.

  Values:

  enumerator ESP_EFUSE_ROM_LOG_ALWAYS_ON

    Always enable ROM logging

  enumerator ESP_EFUSE_ROM_LOG_ON_GPIO_LOW

    ROM logging is enabled when specific GPIO level is low during start up

  enumerator ESP_EFUSE_ROM_LOG_ON_GPIO_HIGH

    ROM logging is enabled when specific GPIO level is high during start up

  enumerator ESP_EFUSE_ROM_LOG_ALWAYS_OFF

    Disable ROM logging permanently

enum esp_efuse_token_type_t

  Values:

  enumerator ESP_EFUSE_TOKEN_FROM_READ

    Dump from the eFUSE read registers (the final, permanently programmed values).

  enumerator ESP_EFUSE_TOKEN_FROM_STAGED

    Dump from write/staging registers or programming buffer (pending or staged writes). This can expose keys in plaintext because it shows values that are not yet burned and not yet read-protected. Requires CONFIG_EFUSE_ENABLE_STAGED_TOKEN_API.

  enumerator ESP_EFUSE_TOKEN_FROM_READ_STAGED

    Combine both read and staged sources to show committed and pending values. The staged portion can expose keys in plaintext because it shows values that are not yet burned and not yet read-protected. Requires CONFIG_EFUSE_ENABLE_STAGED_TOKEN_API.

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