# eFuse 管理器

[English]

## 简介

eFuse 是一种微型的一次性可编程保险丝，可以通过“烧录”（即编程）将数据存储到 ESP32-S31 中。eFuse 位组成不同的数据字段，用于系统参数（即 ESP32-S31 的 ESP-IDF 使用的数据参数）或用户自定义参数。

eFuse 管理器组件中集合了多种工具和 API，可帮助定义、烧录和访问 eFuse 参数。常用的工具和 API 包括：

- 表格格式，用于在 CSV 文件中定义 eFuse 数据字段

- `efuse_table_gen.py` 工具，用于生成 CSV 文件指定的 eFuse 数据字段对应的 C 结构体

- 用于读/写 eFuse 数据字段的 C API 集合

## eFuse Manager 与 `idf.py`

`idf.py` 通过 `idf.py efuse-<subcommand>` 命令为 eFuse 管理器提供了部分功能。本文档主要使用基于 `idf.py` 的命令，只有在涉及高级功能或罕见情况时，会使用基于 `espefuse` 的命令。要查看所有可用的命令，请运行 `idf.py --help` 并搜索以 `efuse-` 为前缀的命令。

## 硬件描述

ESP32-S31 有多个 eFuse，可用于存储系统参数和用户参数。每个 eFuse 都是一个一位字段，可以烧写为 1，之后就不能再恢复为 0。eFuse 位被分成了多个 256 位的块，每个块又被分成 8 个 32 位寄存器。部分块保留用于系统参数，其它块可用于用户参数。

如需了解更多内容，请参阅 ESP32-S31 技术参考手册 > eFuse 控制器 (eFuse) [PDF]。

ESP32-S31 有 11 个 eFuse 块，每个块的大小为 256 位（并非所有位都可用于用户参数）：

- EFUSE_BLK0 完全用于系统参数；

- EFUSE_BLK1 完全用于系统参数；

- EFUSE_BLK2 完全用于系统参数；

- EFUSE_BLK3（也称为 EFUSE_BLK_USER_DATA）可用于用户参数；

- EFUSE_BLK4 至 EFUSE_BLK8（即 EFUSE_BLK_KEY0 至 EFUSE_BLK_KEY4）可以存储安全启动或 flash 加密的密钥。不使用这两个功能时，可以用于用户参数。

- EFUSE_BLK9（即 EFUSE_BLK_KEY5）可用于存储安全启动或 flash 加密的密钥。不使用这两个功能时，可用于用户参数。

- EFUSE_BLK10（即 EFUSE_BLK_SYS_DATA_PART2）保留用于系统参数。

## 定义 eFuse 字段

eFuse 字段通过 CSV 文件中特定格式的表格进行定义。通过这种格式，可定义任意长度和任意位数的 eFuse 字段。

另外，通过这种格式，可以结构化地定义由子字段组成的 eFuse 字段，这意味着一个父 eFuse 字段可能由占用相同 eFuse 位的多个子 eFuse 字段组成。

### 定义格式

一般情况下，每个记录在定义表格中占据一行，每行包含以下值（也就是列）：

    # field_name, efuse_block(EFUSE_BLK0..EFUSE_BLK9), bit_start(0..255), bit_count(1..256), comment

- `field_name`

  > - eFuse 字段的名称。

  > - 字段名称前会自动添加 `ESP_EFUSE_` 前缀，在 C 代码中，可通过此名称来访问 eFuse 字段。

  > - 对于每个 eFuse 字段，`field_name` 必须唯一。

  > - 如果此值为空，说明该行与前一行合并。这样就可以定义任意位排序的 eFuse 字段（例如通用表中的 `MAC_FACTORY` 字段）。

  > - 使用 `.` 来定义一个子 eFuse 字段。详情请参考 结构化 eFuse 字段。

- `efuse_block`

  > - eFuse 字段的块号。例如 EFUSE_BLK0 到 EFUSE_BLK9。

  > - 这一字段决定了 eFuse 字段在哪个块中。

- `bit_start`

  > - eFuse 字段在块内的位置偏移（0 至 255 位）。

  > - `bit_start` 是可选项，可省略。

  >   > - 当省略时，如果上一条记录位于同一个 eFuse 块中，`bit_start` 会被设置为上一条记录的 `bit_start + bit_count`。

  >   > - 如果上一条记录位于不同的 eFuse 块中，则会报错。

- `bit_count`

  > - eFuse 字段的大小，以位为单位（1 至 N）。

  > - `bit_count` 不能省略

  > - 如将其设置为 `MAX_BLK_LEN`，则此 eFuse 字段为块中允许的最大 eFuse 字段大小。

- `comment`

  > - 描述 eFuse 字段的注释。

  > - 此注释会逐字复制到 C 头文件中。

如果一个 eFuse 字段需要非顺序位序，那么该 eFuse 字段将占用多行。应在第一行的 `field_name` 处定该 eFuse 字段的名称，并且将其他行的 `field_name` 留空。这样就表明这些行属于同一个 eFuse 字段。

以下示例中定义了两个 eFuse 字段。首先定义非连续的 eFuse 字段 `MAC_FACTORY`，然后定义了常规 eFuse 字段 `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

在 C 代码中，可以通过 `ESP_EFUSE_MAC_FACTORY` 和 `ESP_EFUSE_MAC_FACTORY_CRC` 使用这两个字段。

## 结构化 eFuse 字段

通常情况下，一个 eFuse 字段代表一个特定的参数。不过，在某些情况下，一个 eFuse 字段可能由多个子字段组成，因此有必要隔离访问这些子字段。例如，如果一个 eFuse 字段包含一个浮点参数，则可以将浮点的符号、指数和尾数字段作为单独的 eFuse 字段进行访问。

因此，可以在 `field_name` 中使用 `.` 操作符，以结构化的方式定义 eFuse 字段。例如，`XX.YY.ZZ` 定义了一个 eFuse 字段 `ZZ`，它是 eFuse 字段 `YY` 的子字段，而 `YY` 又是 eFuse 字段 `XX` 的子字段。

以下示例展示了如何以定义结构化 eFuse 字段：

    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

在上例中可以看出：

- `WR_DIS` 为父 eFuse 字段。其他所有行的 `field_name` 都具有 `WR_DIS.` 前缀，因此都是 `WR_DIS` 的子字段。

- 子字段必须与父字段使用相同的位。注意子字段和父字段的 `bit_start` 和 `bit_count`：

  > - 子字段的位总是在其父字段范围内。例如，`WR_DIS.RD_DIS` 和 `WR_DIS.RD_DIS` 占用了 `WR_DIS` 的第一位和第二位。

  > - 子字段使用的位不能重叠（子字段有别名时除外）。

- 可以将别名创建为子字段。例如，`WR_DIS.FIELD_3.ALIAS` 既是 `WR_DIS.FIELD_3` 的子字段，又是别名，因为它们占用的位相同。

所有 eFuse 字段最终都会通过 `efuse_table_gen.py` 工具转换为 C 结构体。每个 C 结构体从 eFuse 字段的 `field_name` 中衍生出标识符，并用 `_` 替换所有的 `.` 符号。以 `WR_DIS.RD_DIS` 和 `WR_DIS.FIELD_2.B1` 为例，这两个 eFuse 字段用 C 语言分别表示为 `ESP_EFUSE_WR_DIS_RD_DIS` 和 `ESP_EFUSE_WR_DIS_FIELD_2_B1`。

`efuse_table_gen.py` 工具还会检查字段是否相互重叠并在字段范围内。如有违反，会生成以下错误：

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

要解决此问题，可使用 `USER_DATA.SERIAL_NUMBER`，让 `SERIAL_NUMBER` 成为 `USER_DATA` 的子字段。

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

要解决此问题，可将 `FIELD.MAJOR_NUMBER` 的 `bit_start` 从 `60` 改为 `0`，使 `MAJOR_NUMBER` 与 `FIELD` 重叠。

## `efuse_table_gen.py` 工具

`efuse_table_gen.py` 工具能够从 CSV 文件生成 C 源文件，其中包含 CSV 文件中定义的 eFuse 字段的对应 C 结构体（类型为 `esp_efuse_desc_t`）。此外，该工具还会在生成 C 源文件前对 CSV 文件进行检查，以确保：

- eFuse 字段的名称唯一

- eFuse 字段使用的位不重叠

如前所述，eFuse 字段可用于存储系统参数或用户参数。由于系统参数 eFuse 字段是 ESP-IDF 和 ESP32-S31 的内在要求，这些 eFuse 字段被定义在 通用 CSV 文件中，即 `esp_efuse_table.csv` 中，是 ESP-IDF 的一部分。对于用户参数 eFuse 字段，用户应在 自定义 CSV 文件（如 `esp_efuse_custom_table.csv`）中进行定义。

要从 通用 CSV 文件生成 C 源文件，运行 `idf.py efuse-common-table` 或以下命令：

    cd $IDF_PATH/components/efuse/
    ./efuse_table_gen.py --idf_target esp32s31 esp32s31/esp_efuse_table.csv

然后，就会在路径 `$IDF_PATH/components/efuse/esp32s31` 中生成以下 C 源文件/头文件：

- `esp_efuse_table.c` 文件，包含系统参数 eFuse 字段的 C 结构体。

- `esp_efuse_table.h` 文件，位于 `include` 文件夹。应用程序可包含该头文件，以使用上述 C 结构体。

要使用 自定义 CSV 文件生成 C 源文件，请运行 `idf.py efuse-custom-table` 或以下命令：

    cd $IDF_PATH/components/efuse/
    ./efuse_table_gen.py --idf_target esp32s31 esp32s31/esp_efuse_table.csv PROJECT_PATH/main/esp_efuse_custom_table.csv

然后在 `PROJECT_PATH/main` 路径下生成 C 源/头文件：

- `esp_efuse_custom_table.c` 文件，包含用户参数 eFuse 字段的 C 结构体。

- `esp_efuse_custom_table.h` 文件，位于 `include` 文件夹。应用程序可包含该头文件，以使用上述 C 结构体。

要使用生成的字段，需添加以下头文件：

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

## 支持的编码方式

eFuse 支持各种编码方式，能够检测或纠正错误，保护 eFuse 数据不受损坏。

ESP32-S31 不支持选择编码方式，会自动将以下编码方案应用于各 eFuse 块：

- `非编码` 方式，应用于 EFUSE_BLK0。

- `RS 编码` 方式。应用于 EFUSE_BLK1 - EFUSE_BLK9。

### `非编码` 方式

`非编码` 方式会自动应用于 EFUSE_BLK0。此方式不涉及任何编码，只是在硬件中维护 EFUSE_BLK0 的四个备份，因此，每个位实际存储四次，EFUSE_BLK0 也可以多次写入。

该方案由硬件自动应用，软件中不可见。

### `RS 编码` 方式

- `RS 编码` 方式，即 Reed-Solomon 编码方式，会自动应用于 EFUSE_BLK1 至 EFUSE_BLK9。该编码方式支持至多 6 个字节的自动纠错。

软件使用 `RS(44, 32)` 对 32 字节的 EFUSE_BLKx 进行编码，生成一个 12 字节的校验码，然后将 EFUSE_BLKx 和校验码同时烧录到 eFuse 中。

在回读 eFuse 块时，eFuse 控制器会对 `RS 编码` 进行自动解码和纠错。因为 `RS` 校验码是根据整个 256 位 eFuse 块生成的，所以每个块只能写入一次，且必须采用批量写入模式。

### 批量写入模式

如需在运行时写入 eFuse 字段，可能要采用批量写入模式，具体取决于 eFuse 块使用的编码方案。批量写入模式的使用步骤如下：

1. 调用 `esp_efuse_batch_write_begin()` 启用批量写入模式。

2. 使用各 `esp_efuse_write_...` 函数，按照常规方法写入 eFuse 字段。

3. 完成所有写入后，调用 `esp_efuse_batch_write_commit()` 将准备好的数据烧录到 eFuse 块中。

警告

如果 eFuse 块中已经存在通过 `Reed-Solomon` 编码方案预先写入的数据，则无法在不破坏先前数据校验和/校验符号的情况下，写入额外的内容（即使需要写入的位为空）。

先前的校验和/校验符号会被新的校验和/校验符号覆盖，并完全销毁。（但不会损坏有效负载 eFuse）。

如发现在 CUSTOM_MAC、SPI_PAD_CONFIG_HD、SPI_PAD_CONFIG_CS 等块中存在预写入数据，请联系乐鑫获取所需的预烧录 eFuse。

仅供测试（不推荐）：可以忽略或抑制违反编码方式数据的错误，从而在 eFuse 块中烧录必要的位。

## eFuse API

可以通过指向描述结构的指针来访问 eFuse 字段。API 函数可以实现一些基本操作：

- `esp_efuse_read_field_blob()` - 返回读取的 eFuse 位的数组。

- `esp_efuse_read_field_cnt()` - 返回烧写为 “1” 的位的数量。

- `esp_efuse_write_field_blob()` - 写入一个数组。

- `esp_efuse_write_field_cnt()` - 将所需数量的位写为 “1”。

- `esp_efuse_get_field_size()` - 返回字段的位数。

- `esp_efuse_read_reg()` - 返回 eFuse 寄存器的值。

- `esp_efuse_write_reg()` - 将值写入 eFuse 寄存器。

- `esp_efuse_get_coding_scheme()` - 返回块的 eFuse 编码方式。

- `esp_efuse_read_block()` - 从指定偏移位置开始读取指定大小的 eFuse 块中的密钥。

- `esp_efuse_write_block()` - 从指定偏移位置开始将密钥写入指定大小的 eFuse 块中。

- `esp_efuse_batch_write_begin()` - 设置字段写入的批处理模式。

- `esp_efuse_batch_write_commit()` - 写入所有为批处理写入模式准备的数据，并重置批处理写入模式。

- `esp_efuse_batch_write_cancel()` - 重置批处理写入模式和准备的数据。

- `esp_efuse_get_key_dis_read()` - 返回密钥块的读保护状态。

- `esp_efuse_set_key_dis_read()` - 设置密钥块的读保护状态。

- `esp_efuse_get_key_dis_write()` - 返回密钥块的写保护状态。

- `esp_efuse_set_key_dis_write()` - 设置密钥块的写保护状态。

- `esp_efuse_get_key_purpose()` - 返回 eFuse 密钥块当前设置的用途。

- `esp_efuse_write_key()` - 将一块密钥数据烧写到一个 eFuse 块。

- `esp_efuse_write_keys()` - 将密钥烧写到未使用的 eFuse 块。

- `esp_efuse_find_purpose()` - 查找设置为特定用途的密钥块。

- `esp_efuse_get_keypurpose_dis_write()` - 返回 eFuse 密钥块的密钥用途字段的写保护状态（对于 esp32 始终为 true）。

- `esp_efuse_key_block_unused()` - 如果密钥块未使用，则返回 true，否则返回 false。

- `esp_efuse_destroy_block()` - 销毁此 eFuse 块中的数据。该函数有两个作用：(1) 如果未开启写保护，则将不为 1 的位都烧写为 1；(2) 如果未开启读保护，则开启读保护。

经常使用的字段有专门的函数可供使用，例如 `esp_efuse_get_pkg_ver()`。

## eFuse 密钥 API

EFUSE_BLK_KEY0 - EFUSE_BLK_KEY5 可以保存 6 个长度为 256 位的密钥。每个密钥都有一个 `ESP_EFUSE_KEY_PURPOSE_x` 字段说明密钥用途。用途字段描述见 `esp_efuse_purpose_t`。

类似 `ESP_EFUSE_KEY_PURPOSE_XTS_AES_...` 的用途用于 flash 加密。

类似 `ESP_EFUSE_KEY_PURPOSE_SECURE_BOOT_DIGEST...` 的用途用于安全启动。

一些 eFuse API 可用于处理密钥状态：

- `esp_efuse_get_purpose_field()` - 返回一个指向 eFuse 密钥块的密钥用途的指针。

- `esp_efuse_get_key()` - 返回一个指向密钥块的指针。

- `esp_efuse_set_key_purpose()` - 为一个 eFuse 密钥块设置密钥用途。

- `esp_efuse_set_keypurpose_dis_write()` - 为 eFuse 密钥块的密钥用途字段设置写保护。

- `esp_efuse_find_unused_key_block()` - 搜索未使用的密钥块并返回找到的第一个结果。

- `esp_efuse_count_unused_key_blocks()` - 返回 EFUSE_BLK_KEY0..EFUSE_BLK_KEY_MAX 范围中未使用的 eFuse 密钥块数量。

- `esp_efuse_get_digest_revoke()` - 返回安全启动公钥摘要撤销位的状态。

- `esp_efuse_set_digest_revoke()` - 设置安全启动公钥摘要撤销位。

- `esp_efuse_get_write_protect_of_digest_revoke()` - 返回安全启动公钥摘要撤销位的写保护。

- `esp_efuse_set_write_protect_of_digest_revoke()` - 设置安全启动公钥摘要撤销位的写保护。

## 如何添加新字段

1. 为新字段查找空闲位。运行 `idf.py show-efuse-table` 查看 `esp_efuse_table.csv` 文件，或运行以下命令：

    $ ./efuse_table_gen.py -t esp32s31 esp32s31/esp_efuse_table.csv --info

    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_RND_SWITCH_CYCLE         EFUSE_BLK0        1            1
    4     WR_DIS.KM_DISABLE_DEPLOY_MODE      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.WDT_DELAY_SEL               EFUSE_BLK0        2            1
    18     WR_DIS.SECURE_BOOT_DISABLE_FAST_WAKE     EFUSE_BLK0        2            1
    19     WR_DIS.DIS_WDT                     EFUSE_BLK0        2            1
    20     WR_DIS.DIS_SWD                     EFUSE_BLK0        2            1
    21     WR_DIS.PMU_FLASH_POWER_SEL         EFUSE_BLK0        2            1
    22     WR_DIS.PMU_FLASH_POWER_SEL_EN      EFUSE_BLK0        2            1
    23     WR_DIS.POWER_GLITCH_EN             EFUSE_BLK0        2            1
    24     WR_DIS.PVT_0_GLITCH_EN             EFUSE_BLK0        3            1
    25     WR_DIS.PVT_0_GLITCH_MODE           EFUSE_BLK0        3            1
    26     WR_DIS.PVT_1_GLITCH_EN             EFUSE_BLK0        3            1
    27     WR_DIS.PVT_1_GLITCH_MODE           EFUSE_BLK0        3            1
    28     WR_DIS.SPI_BOOT_CRYPT_CNT          EFUSE_BLK0        4            1
    29     WR_DIS.SECURE_BOOT_KEY_REVOKE0     EFUSE_BLK0        5            1
    30     WR_DIS.SECURE_BOOT_KEY_REVOKE1     EFUSE_BLK0        6            1
    31     WR_DIS.SECURE_BOOT_KEY_REVOKE2     EFUSE_BLK0        7            1
    32     WR_DIS.KEY_PURPOSE_0               EFUSE_BLK0        8            1
    33     WR_DIS.KEY_PURPOSE_1               EFUSE_BLK0        9            1
    34     WR_DIS.KEY_PURPOSE_2               EFUSE_BLK0        10           1
    35     WR_DIS.KEY_PURPOSE_3               EFUSE_BLK0        11           1
    36     WR_DIS.KEY_PURPOSE_4               EFUSE_BLK0        12           1
    37     WR_DIS.DIS_SM_CRYPT                EFUSE_BLK0        14           1
    38     WR_DIS.ECC_FORCE_CONST_TIME        EFUSE_BLK0        14           1
    39     WR_DIS.ECDSA_DISABLE_SOFT_K        EFUSE_BLK0        14           1
    40     WR_DIS.SEC_DPA_LEVEL               EFUSE_BLK0        14           1
    41     WR_DIS.XTS_DPA_CLK_ENABLE          EFUSE_BLK0        14           1
    42     WR_DIS.XTS_DPA_PSEUDO_LEVEL        EFUSE_BLK0        14           1
    43     WR_DIS.RMA_NONCE_ENA               EFUSE_BLK0        14           1
    44     WR_DIS.RMA_CHIP_INFO_SOURCE        EFUSE_BLK0        14           1
    45     WR_DIS.RMA_DISABLE_FAST_VEF        EFUSE_BLK0        14           1
    46     WR_DIS.ENA_XTS_SHADOW              EFUSE_BLK0        14           1
    47     WR_DIS.ENA_SPI_BOOT_CRYPT_SCRAMBLER     EFUSE_BLK0        14           1
    48     WR_DIS.RE_ENABLE_JTAG_SOURCE       EFUSE_BLK0        14           1
    49     WR_DIS.SECURE_BOOT_EN              EFUSE_BLK0        15           1
    50     WR_DIS.SECURE_BOOT_AGGRESSIVE_REVOKE     EFUSE_BLK0        16           1
    51     WR_DIS.FLASH_TYPE                  EFUSE_BLK0        18           1
    52     WR_DIS.DIS_USB_OTG_DOWNLOAD_MODE     EFUSE_BLK0        18           1
    53     WR_DIS.FLASH_TPUW                  EFUSE_BLK0        18           1
    54     WR_DIS.DIS_DOWNLOAD_MODE           EFUSE_BLK0        18           1
    55     WR_DIS.DIS_DIRECT_BOOT             EFUSE_BLK0        18           1
    56     WR_DIS.DIS_USB_SERIAL_JTAG_ROM_PRINT     EFUSE_BLK0        18           1
    57     WR_DIS.DIS_USB_SERIAL_JTAG_DOWNLOAD_MODE     EFUSE_BLK0        18           1
    58     WR_DIS.ENABLE_SECURITY_DOWNLOAD     EFUSE_BLK0        18           1
    59     WR_DIS.UART_PRINT_CONTROL          EFUSE_BLK0        18           1
    60     WR_DIS.FORCE_SEND_RESUME           EFUSE_BLK0        18           1
    61     WR_DIS.SECURE_VERSION              EFUSE_BLK0        18           1
    62     WR_DIS.HUK_GEN_STATE               EFUSE_BLK0        19           1
    63     WR_DIS.BLK1                        EFUSE_BLK0        20           1
    64     WR_DIS.MAC                         EFUSE_BLK0        20           1
    65     WR_DIS.MAC_EXT                     EFUSE_BLK0        20           1
    66     WR_DIS.WAFER_VERSION_MINOR         EFUSE_BLK0        20           1
    67     WR_DIS.WAFER_VERSION_MAJOR         EFUSE_BLK0        20           1
    68     WR_DIS.DISABLE_WAFER_VERSION_MAJOR     EFUSE_BLK0        20           1
    69     WR_DIS.DISABLE_BLK_VERSION_MAJOR     EFUSE_BLK0        20           1
    70     WR_DIS.BLK_VERSION_MINOR           EFUSE_BLK0        20           1
    71     WR_DIS.BLK_VERSION_MAJOR           EFUSE_BLK0        20           1
    72     WR_DIS.PSRAM_CAP                   EFUSE_BLK0        20           1
    73     WR_DIS.TEMP                        EFUSE_BLK0        20           1
    74     WR_DIS.PSRAM_VENDOR                EFUSE_BLK0        20           1
    75     WR_DIS.PKG_VERSION                 EFUSE_BLK0        20           1
    76     WR_DIS.SYS_DATA_PART1              EFUSE_BLK0        21           1
    77     WR_DIS.OPTIONAL_UNIQUE_ID          EFUSE_BLK0        21           1
    78     WR_DIS.BLOCK_USR_DATA              EFUSE_BLK0        22           1
    79     WR_DIS.CUSTOM_MAC                  EFUSE_BLK0        22           1
    80     WR_DIS.BLOCK_KEY0                  EFUSE_BLK0        23           1
    81     WR_DIS.BLOCK_KEY1                  EFUSE_BLK0        24           1
    82     WR_DIS.BLOCK_KEY2                  EFUSE_BLK0        25           1
    83     WR_DIS.BLOCK_KEY3                  EFUSE_BLK0        26           1
    84     WR_DIS.BLOCK_KEY4                  EFUSE_BLK0        27           1
    85     WR_DIS.BLOCK_SYS_DATA2             EFUSE_BLK0        28           1
    86     WR_DIS.USB_DEVICE_EXCHG_PINS       EFUSE_BLK0        28           1
    87     WR_DIS.SOFT_DIS_JTAG               EFUSE_BLK0        31           1
    88     RD_DIS                             EFUSE_BLK0        32           7
    89     RD_DIS.BLOCK_KEY0                  EFUSE_BLK0        32           1
    90     RD_DIS.BLOCK_KEY1                  EFUSE_BLK0        33           1
    91     RD_DIS.BLOCK_KEY2                  EFUSE_BLK0        34           1
    92     RD_DIS.BLOCK_KEY3                  EFUSE_BLK0        35           1
    93     RD_DIS.BLOCK_KEY4                  EFUSE_BLK0        36           1
    94     DIS_USB_JTAG                       EFUSE_BLK0        42           1
    95     DIS_FORCE_DOWNLOAD                 EFUSE_BLK0        44           1
    96     SPI_DOWNLOAD_MSPI_DIS              EFUSE_BLK0        45           1
    97     DIS_TWAI                           EFUSE_BLK0        46           1
    98     JTAG_SEL_ENABLE                    EFUSE_BLK0        47           1
    99     SOFT_DIS_JTAG                      EFUSE_BLK0        48           3
    100     DIS_PAD_JTAG                       EFUSE_BLK0        51           1
    101     DIS_DOWNLOAD_MANUAL_ENCRYPT        EFUSE_BLK0        52           1
    102     HUK_GEN_STATE                      EFUSE_BLK0        55           5
    103     KM_RND_SWITCH_CYCLE                EFUSE_BLK0        64           1
    104     KM_DISABLE_DEPLOY_MODE             EFUSE_BLK0        66           5
    105     KM_DEPLOY_ONLY_ONCE                EFUSE_BLK0        71           5
    106     FORCE_USE_KEY_MANAGER_KEY          EFUSE_BLK0        76           5
    107     FORCE_DISABLE_SW_INIT_KEY          EFUSE_BLK0        81           1
    108     KM_XTS_KEY_LENGTH_256              EFUSE_BLK0        82           1
    109     WDT_DELAY_SEL                      EFUSE_BLK0        83           1
    110     DIS_SM_CRYPT                       EFUSE_BLK0        84           1
    111     SPI_BOOT_CRYPT_CNT                 EFUSE_BLK0        85           3
    112     SECURE_BOOT_KEY_REVOKE0            EFUSE_BLK0        88           1
    113     SECURE_BOOT_KEY_REVOKE1            EFUSE_BLK0        89           1
    114     SECURE_BOOT_KEY_REVOKE2            EFUSE_BLK0        90           1
    115     KEY_PURPOSE_0                      EFUSE_BLK0        96           5
    116     KEY_PURPOSE_1                      EFUSE_BLK0       101           5
    117     KEY_PURPOSE_2                      EFUSE_BLK0       106           5
    118     KEY_PURPOSE_3                      EFUSE_BLK0       111           5
    119     KEY_PURPOSE_4                      EFUSE_BLK0       116           5
    120     ECC_FORCE_CONST_TIME               EFUSE_BLK0       121           1
    121     ECDSA_DISABLE_SOFT_K               EFUSE_BLK0       122           1
    122     SEC_DPA_LEVEL                      EFUSE_BLK0       123           2
    123     XTS_DPA_CLK_ENABLE                 EFUSE_BLK0       125           1
    124     XTS_DPA_PSEUDO_LEVEL               EFUSE_BLK0       128           2
    125     SECURE_BOOT_EN                     EFUSE_BLK0       130           1
    126     SECURE_BOOT_AGGRESSIVE_REVOKE      EFUSE_BLK0       131           1
    127     FLASH_TYPE                         EFUSE_BLK0       133           1
    128     DIS_USB_OTG_DOWNLOAD_MODE          EFUSE_BLK0       137           1
    129     FLASH_TPUW                         EFUSE_BLK0       140           4
    130     DIS_DOWNLOAD_MODE                  EFUSE_BLK0       144           1
    131     DIS_DIRECT_BOOT                    EFUSE_BLK0       145           1
    132     DIS_USB_SERIAL_JTAG_ROM_PRINT      EFUSE_BLK0       146           1
    133     LOCK_KM_KEY                        EFUSE_BLK0       147           1
    134     DIS_USB_SERIAL_JTAG_DOWNLOAD_MODE     EFUSE_BLK0       148           1
    135     ENABLE_SECURITY_DOWNLOAD           EFUSE_BLK0       149           1
    136     UART_PRINT_CONTROL                 EFUSE_BLK0       150           2
    137     FORCE_SEND_RESUME                  EFUSE_BLK0       152           1
    138     SECURE_VERSION                     EFUSE_BLK0       160           16
    139     SECURE_BOOT_DISABLE_FAST_WAKE      EFUSE_BLK0       176           1
    140     HYS_EN_PAD                         EFUSE_BLK0       177           1
    141     DCDC_VSET_EN                       EFUSE_BLK0       194           1
    142     DIS_WDT                            EFUSE_BLK0       195           1
    143     DIS_SWD                            EFUSE_BLK0       196           1
    144     SECURE_BOOT_SHA384_EN              EFUSE_BLK0       203           1
    145     BOOTLOADER_ANTI_ROLLBACK_SECURE_VERSION     EFUSE_BLK0       204           4
    146     BOOTLOADER_ANTI_ROLLBACK_EN        EFUSE_BLK0       208           1
    147     BOOTLOADER_ANTI_ROLLBACK_UPDATE_IN_ROM     EFUSE_BLK0       209           1
    148     RECOVERY_BOOTLOADER_FLASH_SECTOR     EFUSE_BLK0       210           12
    149     RMA_ENA                            EFUSE_BLK0       222           2
    150     RMA_SESSION_COUNTER                EFUSE_BLK0       224           3
    151     RMA_NONCE_ENA                      EFUSE_BLK0       227           2
    152     RMA_CHIP_INFO_SOURCE               EFUSE_BLK0       229           1
    153     RMA_DISABLE_FAST_VEF               EFUSE_BLK0       230           1
    154     PVT_0_GLITCH_EN                    EFUSE_BLK0       231           1
    155     PVT_0_GLITCH_MODE                  EFUSE_BLK0       232           2
    156     PVT_1_GLITCH_EN                    EFUSE_BLK0       234           1
    157     PVT_1_GLITCH_MODE                  EFUSE_BLK0       235           2
    158     PMU_FLASH_POWER_SEL                EFUSE_BLK0       237           1
    159     PMU_FLASH_POWER_SEL_EN             EFUSE_BLK0       238           1
    160     POWER_GLITCH_EN                    EFUSE_BLK0       239           4
    161     ENA_XTS_SHADOW                     EFUSE_BLK0       243           1
    162     ENA_SPI_BOOT_CRYPT_SCRAMBLER       EFUSE_BLK0       244           1
    163     RE_ENABLE_JTAG_SOURCE              EFUSE_BLK0       245           1
    164     MAC                                EFUSE_BLK1        0            8
    165     MAC                                EFUSE_BLK1        8            8
    166     MAC                                EFUSE_BLK1        16           8
    167     MAC                                EFUSE_BLK1        24           8
    168     MAC                                EFUSE_BLK1        32           8
    169     MAC                                EFUSE_BLK1        40           8
    170     MAC_EXT                            EFUSE_BLK1        48           8
    171     MAC_EXT                            EFUSE_BLK1        56           8
    172     WAFER_VERSION_MINOR                EFUSE_BLK1       114           4
    173     WAFER_VERSION_MAJOR                EFUSE_BLK1       118           2
    174     DISABLE_WAFER_VERSION_MAJOR        EFUSE_BLK1       120           1
    175     DISABLE_BLK_VERSION_MAJOR          EFUSE_BLK1       121           1
    176     BLK_VERSION_MINOR                  EFUSE_BLK1       122           3
    177     BLK_VERSION_MAJOR                  EFUSE_BLK1       125           2
    178     PSRAM_CAP                          EFUSE_BLK1       127           3
    179     TEMP                               EFUSE_BLK1       130           2
    180     PSRAM_VENDOR                       EFUSE_BLK1       132           2
    181     PKG_VERSION                        EFUSE_BLK1       134           2
    182     OPTIONAL_UNIQUE_ID                 EFUSE_BLK2        0           128
    183     USER_DATA                          EFUSE_BLK3        0           256
    184     USER_DATA.MAC_CUSTOM               EFUSE_BLK3       200           48
    185     KEY0                               EFUSE_BLK4        0           256
    186     KEY1                               EFUSE_BLK5        0           256
    187     KEY2                               EFUSE_BLK6        0           256
    188     KEY3                               EFUSE_BLK7        0           256
    189     KEY4                               EFUSE_BLK8        0           256
    190     SYS_DATA_PART2                     EFUSE_BLK9        0            32
    191     USB_DEVICE_EXCHG_PINS              EFUSE_BLK9       192           1

    Used bits in efuse table:
    EFUSE_BLK0
    [0 31] [0 1] [1 1] [1 1] ... [140 152] [160 177] [194 196] [203 245]

    EFUSE_BLK1
    [0 63] [114 135]

    EFUSE_BLK2
    [0 127]

    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 31] [192 192]

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

不包含在方括号中的位是空闲的（一些位是乐鑫的保留位）。已检查所有字段的位重叠情况。

要在现有字段中添加子字段，请参考 结构化 eFuse 字段。例如，可使用 `.` 操作符将字段 `SERIAL_NUMBER`、`MODEL_NUMBER` 和 `HARDWARE_REV` 添加到现有的 `USER_DATA` 字段中，如下所示：

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

通常按照如下步骤添加新的 eFuse 字段：

1. 在 CSV 文件中为每个 eFuse 字段添加一行记录。

2. 运行 `show_efuse_table` 命令检查 eFuse 表。

3. 如要生成源文件，运行 `efuse_common_table` 或 `efuse_custom_table` 命令。

如果遇到 `intersects with` 或 `out of range` 等错误，请参阅 结构化 eFuse 字段 中的解决办法。

## 位序

eFuse 位序采取小字节序（参见下方示例），这说明 eFuse 位按照从 LSB 到 MSB 的顺序进行读写：

    $ 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

例如，CSV 文件描述了 `USER_DATA` 字段，该字段占用 256 位，即一个完整的块。

    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]

因此，读取如上 eFuse `USER_DATA` 块会得到以下结果：

    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; // 可以用于这种情况，因为它只包含一个条目
    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); // 只读取前两位
    // field1 = 0x0002

    uint8_t id = 0;
    size_t id_size = esp_efuse_get_field_size(ESP_EFUSE_ID); // 返回 6
    // size_t id_size = ESP_EFUSE_USER_DATA[0]->bit_count; // 不能用于这种情况，因为其中包含 3 个条目，会返回 3 而不是 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

## 在构建阶段获取 eFuse 状态

要在项目的构建阶段获取 eFuse 状态，可以使用以下两个 CMake 函数：

- `espefuse_get_json_summary()` - 调用 `espefuse summary --format json` 命令并返回一个 JSON 字符串（该字符串不存储在文件中）。

- `espefuse_get_efuse()` - 在此 JSON 字符串中找到给定的 eFuse 名称并返回其属性。

该 JSON 字符串具有以下属性：

    {
        "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
        },
    }

可以通过项目顶层目录下的 `CMakeLists.txt` (system/efuse/CMakeLists.txt) 来使用这些函数：

    # ...
    project(hello_world)

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

`value` 属性的格式与 `espefuse summary` 或 `idf.py efuse-summary` 中显示的格式相同。

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

在示例测试 system/efuse/CMakeLists.txt 中，添加了一个自定义目标 `efuse-filter`。这样，不仅在项目构建阶段，而在任何时候都可以运行 `idf.py efuse-filter` 命令读取所需的 eFuse（在 `efuse_names` 列表中指定）。

## 调试 eFuse & 单元测试

### 虚拟 eFuse

Kconfig 选项 CONFIG_EFUSE_VIRTUAL 在 eFuse 管理器中虚拟了 eFuse 值，因此写入操作是仿真操作，不会永久更改 eFuse 值。这对于应用程序调试和单元测试很有用处。

在启动时，eFuses 被复制到 RAM 中。此时，所有的 eFuse 操作（读和写）都是通过 RAM 执行，而不是通过实际的 eFuse 寄存器执行的。

除了 CONFIG_EFUSE_VIRTUAL 选项外，还有 CONFIG_EFUSE_VIRTUAL_KEEP_IN_FLASH 选项，该选项可将 eFuse 保留在 flash 内存中。要使用此模式，partition_table 在 `partition.csv` 中包含名为 `efuse` 的分区：

    efuse_em, data, efuse,   ,   0x2000,

在启动阶段，eFuse 会从 flash 中复制到 RAM 中，在 flash 为空的情况下，则从实际的 eFuse 复制到 RAM 中，然后更新 flash。此选项能够在重启后仍然保留 eFuse，用于测试安全启动和 flash 加密功能。

#### flash 加密测试

flash 加密是一项硬件功能，需要物理烧录 eFuse `key` 和 `FLASH_CRYPT_CNT`。如果 flash 加密实际未启用，那么启用 CONFIG_EFUSE_VIRTUAL_KEEP_IN_FLASH 选项只是提供了测试的可能性，而不会加密 flash 中的任何内容，即使日志中显示了加密操作。

为此，可使用 `bootloader_flash_write()` 函数。但是，如果运行应用程序时芯片已启用 flash 加密，或者以 CONFIG_EFUSE_VIRTUAL_KEEP_IN_FLASH 选项创建了引导加载程序，则 flash 加密/解密操作会正常进行。这意味着数据写入加密 flash 分区时被加密，从加密分区读取时被解密。

### `espefuse`

esptool 中包含一个用于读取/写入 ESP32-S31 eFuse 位的有用工具： espefuse。

`idf.py` 命令也可以直接提供上述工具的部分功能。例如，运行 `idf.py efuse-summary` 命令，效果等同于 `espefuse summary`。

    idf.py efuse-summary

    Executing action: efuse-summary
    (...)

    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)
    RESERVED_0_39 (BLOCK0)                             Enable usb device exchange pins of D+ and D-       = 0 R/W (0b000)
    DIS_TWAI (BLOCK0)                                  Represents whether TWAI function is disabled or en = False R/W (0b0)
                                                       abled. 1: disabled. 0: enabled
    EFUSE_DIS_WIFI6 (BLOCK0)                           USB intphy of usb device signle-end input high thr = False R/W (0b0)
                                                       eshold; 1.76V to 2V. Step by 80mV
    KM_HUK_GEN_STATE (BLOCK0)                          Set this bit to control validation of HUK generate = 0 R/W (0b00000)
                                                        mode. Odd of 1 is invalid; even of 1 is valid
    KM_RND_SWITCH_CYCLE (BLOCK0)                       Set bits to control key manager random number swit = False R/W (0b0)
                                                       ch cycle. 0: control by register. 1: 8 km clk cycl
                                                       es. 2: 16 km cycles. 3: 32 km cycles
    KM_DISABLE_DEPLOY_MODE (BLOCK0)                    Set bits to control key manager random number swit = 0 R/W (0b00000)
                                                       ch cycle. 0: control by register. 1: 8 km clk cycl
                                                       es. 2: 16 km cycles. 3: 32 km cycles
    KM_DEPLOY_ONLY_ONCE (BLOCK0)                       Set each bit to control whether corresponding key  = 0 R/W (0b00000)
                                                       can only be deployed once. 1 is true; 0 is false.
                                                       Bit0: ecdsa. Bit1: xts. Bit2: hmac. Bit3: ds
    ECC_FORCE_CONST_TIME (BLOCK0)                      Represents the spa secure level by configuring the = False R/W (0b0)
                                                        clock random divide mode
    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 r
                                                       eset at low level. 10: enable printing when GPIO8
                                                       is reset at high level. 11: force disable printing
    HYS_EN_PAD (BLOCK0)                                Represents whether the hysteresis function of      = False R/W (0b0)
                                                       corresponding PAD is enabled. 1: enabled. 0:disabled
    DCDC_VSET_EN (BLOCK0)                              Select dcdc vset use efuse_dcdc_vset               = False R/W (0b0)
    DIS_SWD (BLOCK0)                                   Set this bit to disable super-watchdog             = False R/W (0b0)
    BOOTLOADER_ANTI_ROLLBACK_EN (BLOCK0)               HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    BOOTLOADER_ANTI_ROLLBACK_UPDATE (BLOCK0)           HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    RMA_ENA (BLOCK0)                                   HP system power source select. 0:LDO. 1: DCDC      = 0 R/W (0b00)
    RMA_SESSION_COUNTER (BLOCK0)                       HP system power source select. 0:LDO. 1: DCDC      = 0 R/W (0b000)
    RMA_NONCE_ENA (BLOCK0)                             HP system power source select. 0:LDO. 1: DCDC      = 0 R/W (0b00)
    RMA_CHIP_INFO_SOURCE (BLOCK0)                      HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    RMA_DISABLE_FAST_VEF (BLOCK0)                      HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    PVT_0_GLITCH_EN (BLOCK0)                           HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    PVT_0_GLITCH_MODE (BLOCK0)                         HP system power source select. 0:LDO. 1: DCDC      = 0 R/W (0b00)
    PVT_1_GLITCH_EN (BLOCK0)                           HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    PVT_1_GLITCH_MODE (BLOCK0)                         HP system power source select. 0:LDO. 1: DCDC      = 0 R/W (0b00)
    POWER_GLITCH_EN (BLOCK0)                           HP system power source select. 0:LDO. 1: DCDC      = 0 R/W (0x0)
    XTS_SHADOW_EN (BLOCK0)                             HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    SPI_BOOT_CRYPT_SCRAMBLER_EN (BLOCK0)               HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    PSRAM_CAP (BLOCK1)                                 PSRAM capacity                                     = 0 R/W (0b000)
    TEMP (BLOCK1)                                      Operating temperature of the ESP chip              = 0 R/W (0b00)
    PSRAM_VENDOR (BLOCK1)                              PSRAM vendor                                       = 0 R/W (0b00)
    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 (BLOCK9)                           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_TYPE (BLOCK0)                                The type of interfaced flash. 0: four data lines;  = False R/W (0b0)
                                                       1: eight data lines
    FLASH_TPUW (BLOCK0)                                Represents the flash waiting time after power-up;  = 0 R/W (0x0)
                                                       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 for
                                                       ced
    RECOVERY_BOOTLOADER_FLASH_SECTOR (BLOCK0)          HP system power source select. 0:LDO. 1: DCDC      = 0 R/W (0x000)
    PMU_FLASH_POWEL_SEL (BLOCK0)                       HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)
    PMU_FLASH_POWEL_SEL_EN (BLOCK0)                    HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)

    Identity fuses:
    BOOTLOADER_ANTI_ROLLBACK_VERSION (BLOCK0)          HP system power source select. 0:LDO. 1: DCDC      = 0 R/W (0x0)
    WAFER_VERSION_MINOR (BLOCK1)                       Minor chip version                                 = 0 R/W (0x0)
    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:
                                                       disabled
    SOFT_DIS_JTAG (BLOCK0)                             Represents whether JTAG is disabled in soft way. O = 0 R/W (0b000)
                                                       dd number: disabled. Even number: enabled
    DIS_PAD_JTAG (BLOCK0)                              Represents whether JTAG is disabled in the hard wa = False R/W (0b0)
                                                       y(permanently). 1: disabled. 0: enabled
    RE_ENABLE_JTAG_SOURCE (BLOCK0)                     HP system power source select. 0:LDO. 1: DCDC      = False R/W (0b0)

    Mac fuses:
    MAC (BLOCK1)                                       MAC address
       = 00:00:00:00:00:00 (OK) R/W
    CUSTOM_MAC (BLOCK3)                                Custom MAC
       = 00:00:00:00:00:00 (OK) R/W

    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)                     Set this bit to disable accessing MSPI flash/MSPI  = False R/W (0b0)
                                                       ram by SYS AXI matrix during boot_mode_download
    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: disable
                                                       ed. 0: enabled
    FORCE_USE_KEY_MANAGER_KEY (BLOCK0)                 Set each bit to control whether corresponding key  = 0 R/W (0b00000)
                                                       must come from key manager.. 1 is true; 0 is false
                                                       . Bit0: ecdsa. Bit1: xts. Bit2: hmac. Bit3: ds
    FORCE_DISABLE_SW_INIT_KEY (BLOCK0)                 Set this bit to disable software written init key; = False R/W (0b0)
                                                        and force use efuse_init_key
    KM_XTS_KEY_LENGTH_256 (BLOCK0)                     Set this bit to configure flash encryption use xts = False R/W (0b0)
                                                       -128 key; else use xts-256 key
    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)
    ECDSA_ENABLE_SOFT_K (BLOCK0)                       Represents whether hardware random number k is for = False R/W (0b0)
                                                       ced used in ESDCA. 1: force used. 0: not force use
                                                       d
    SEC_DPA_LEVEL (BLOCK0)                             Represents the spa secure level by configuring the = 0 R/W (0b00)
                                                        clock random divide mode
    XTS_DPA_CLK_ENABLE (BLOCK0)                        Represents the spa secure level by configuring the = False R/W (0b0)
                                                        clock random divide mode
    XTS_DPA_PSEUDO_LEVEL (BLOCK0)                      Represents whether anti-dpa attack is enabled. 1:e = 0 R/W (0b00)
                                                       nabled. 0: disabled
    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
    DIS_DOWNLOAD_MODE (BLOCK0)                         Represents whether Download mode is disabled or en = False R/W (0b0)
                                                       abled. 1: disabled. 0: enabled
    LOCK_KM_KEY (BLOCK0)                               TBD                                                = False R/W (0b0)
    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
    SECURE_BOOT_DISABLE_FAST_WAKE (BLOCK0)             Represents whether FAST VERIFY ON WAKE is disabled = False R/W (0b0)
                                                        or enabled when Secure Boot is enabled. 1: disable
                                                       ed. 0: enabled
    SECURE_BOOT_SHA384_EN (BLOCK0)                     Represents whether secure boot is enabled or disab = False R/W (0b0)
                                                       led. 1: enabled. 0: disabled
    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

    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: enable
                                                       d
    DIS_USB_OTG_DOWNLOAD_MODE (BLOCK0)                 Set this bit to disable download via USB-OTG       = False R/W (0b0)
    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: disabled. 0: ena
                                                       bled

    Wdt fuses:
    WDT_DELAY_SEL (BLOCK0)                             Represents whether RTC watchdog timeout threshold  = 0 R/W (0b0)
                                                       is selected at startup. 1: selected. 0: not select
                                                       ed
    DIS_WDT (BLOCK0)                                   Set this bit to disable watch dog                  = False R/W (0b0)

获取所有 eFuse 寄存器的转储数据。

    idf.py efuse-dump

    Executing action: efuse-dump
    Running espefuse in directory <project-directory>
    Executing "espefuse dump --chip esp32s31"...
    espefuse v5.3.dev2

    === Run "dump" command ===
    BLOCK0          (                ) [0 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    MAC_SPI_8M_0    (BLOCK1          ) [1 ] dump: 00000000 00000000 00000000 00000000 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_SYS_DATA2 (BLOCK9          ) [9 ] dump: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

## 延迟烧写 WR_DIS

`WR_DIS` （写禁用）是一个特殊的 eFuse 字段，用于实现永久写保护。`WR_DIS` 中的每个位用于禁止进一步烧写一个（或多个）关联的 eFuse 字段。一旦完成烧写，将无法再修改受影响的 eFuse 字段。

烧写 BLOCK0 中的暂存数据时，`WR_DIS` 的各个位会在所有其他 BLOCK0 数据烧写完成后单独烧写，以确保在出现编码错误时，烧写函数能够通过重试机制进行恢复。这种方式保证了仅在其他 BLOCK0 数据成功烧写后，才对其施加写保护。

## 应用示例

- system/efuse 演示了如何在 ESP32-S31 上使用 eFuse API，展示了从通用和自定义 eFuse 表中读取和写入字段的操作，并解释了虚拟 eFuse 在调试中的用途。

## API 参考

### Header File

- components/efuse/esp32s31/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 ESP32S31.

  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_BLK_KEY_MAX
  enumerator EFUSE_BLK9

    Number of eFuse BLOCK9. SYS_DATA_PART2

  enumerator EFUSE_BLK_SYS_DATA_PART2

    Number of eFuse BLOCK9. 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

    XTS_AES_256 flash key 1

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_256_KEY_2

    XTS_AES_256 flash key 2

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_128_KEY

    XTS_AES_128 flash key

  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

    Digital Signature peripheral key (uses HMAC Downstream mode)

  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

    XTS_AES_256 PSRAM key 1

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_256_PSRAM_KEY_2

    XTS_AES_256 PSRAM key 2

  enumerator ESP_EFUSE_KEY_PURPOSE_XTS_AES_128_PSRAM_KEY

    XTS_AES_128 PSRAM key

  enumerator ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY_P192

    ECDSA private key P-192

  enumerator ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY_P384_L

    ECDSA private key P-384 low part

  enumerator ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY_P384_H

    ECDSA private key P-384 high part

  enumerator ESP_EFUSE_KEY_PURPOSE_SDC_KEY_DIGEST

    SDC key digest

  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.

  备注

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

  参数:

    - 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.

  返回:

    - 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.

  备注

  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.

  备注

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

  备注

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

  参数:

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

  返回:

    - 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.

  备注

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

  参数:

    - 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.

  返回:

    - 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.

  参数:

    - 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.

  返回:

    - 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.

  参数:

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

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

  返回:

    - 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.

  参数:

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

  返回:

    - 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.

  参数:

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

  返回:

    - 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.

  参数:

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

  返回:

    - 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.

  参数:

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

  返回:

    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)

  备注

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

  参数:

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

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

  返回:

    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)

  参数:

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

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

    - val -- [in] Value to write.

  返回:

    - 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.

  备注

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

  参数:

    blk -- [in] Block number of eFuse.

  返回:

    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.

  备注

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

  参数:

    - 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.

  返回:

    - 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.

  参数:

    - 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.

  返回:

    - 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.

  返回:

    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.

  参数:

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

  返回:

    - 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.

  备注

  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.

  备注

  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.

  备注

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

  返回:

    - 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.

  备注

  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.

  参数:

    log_scheme -- Supported ROM log scheme

  返回:

    - 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.

  返回:

    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.

  参数:

    secure_version -- Secure version from app.

  返回:

    - 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.

  参数:

    secure_version -- [in] Secure version from app.

  返回:

    - 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.

  备注

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

  返回:

    - 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.

  返回:

    - 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.

  返回:

    - 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.

  返回:

    - 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.

  参数:

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

  返回:

    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.

  参数:

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

  返回:

    - 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.

  参数:

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

  返回:

    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.

  参数:

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

  返回:

    - 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)

  参数:

    block -- key block to check.

  返回:

    - 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.

  参数:

    - 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.

  返回:

    - 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.

  备注

  For ESP32: no keypurpose, it returns always True.

  参数:

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

  返回:

    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.

  参数:

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

  返回:

    - 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().

  参数:

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

  返回:

    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.

  参数:

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

  返回:

    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.

  参数:

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

    - purpose -- [in] Key purpose.

  返回:

    - 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.

  参数:

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

  返回:

    - 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.

  返回:

    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.

  参数:

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

  返回:

    - 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.

  参数:

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

  返回:

    - 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.

  参数:

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

  返回:

    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.

  参数:

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

  返回:

    - 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.

  备注

  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.

  备注

  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.

  参数:

    - 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.

  返回:

    - 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.

  备注

  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.

  备注

  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.

  参数:

    - 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).

  返回:

    - 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.

  参数:

    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.

  返回:

    - 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.

  备注

  Refers to ESP32-C3 only.

  返回:

    - 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!

  参数:

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

  返回:

    - 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.

### 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.

### 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

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