Controller && VHCI

Application Examples

  • bluetooth/hci/ble_adv_scan_combined demonstrates how to use Bluetooth capabilities for advertising and scanning with a virtual Host Controller Interface (HCI). This example shows how to implement some host functionalities without a host and displays scanned advertising reports from other devices.

  • bluetooth/hci/controller_hci_uart_esp32 demonstrates how to configure the Bluetooth LE Controller's HCI to communicate over UART on ESP32, enabling communication with an external Bluetooth host stack.

  • bluetooth/hci/controller_vhci_ble_adv demonstrates how to use the ESP-IDF VHCI ble_advertising app to perform advertising without a host and display received HCI events from the controller.

API Reference

Header File

  • components/bt/include/esp32/include/esp_bt.h

  • This header file can be included with:

    #include "esp_bt.h"

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

    REQUIRES bt

    or

    PRIV_REQUIRES bt

Functions

esp_err_t esp_ble_tx_power_set(esp_ble_power_type_t power_type, esp_power_level_t power_level)

Set BLE TX power.

Note

Connection TX power should only be set after the connection is established.

Parameters

  • power_type -- [in] The type of TX power. It could be Advertising, Connection, Default, etc.

  • power_level -- [in] Power level (index) corresponding to the absolute value (dBm)

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_ARG: Invalid argument

esp_power_level_t esp_ble_tx_power_get(esp_ble_power_type_t power_type)

Get BLE TX power.

Note

Connection TX power should only be retrieved after the connection is established.

Parameters

power_type -- [in] The type of TX power. It could be Advertising/Connection/Default and etc.

Returns

  • Power level

esp_err_t esp_bredr_tx_power_set(esp_power_level_t min_power_level, esp_power_level_t max_power_level)

Set BR/EDR TX power.

BR/EDR power control will use the power within the range of minimum value and maximum value. The power level will affect the global BR/EDR TX power for operations such as inquiry, page, and connection.

Note

  1. Please call this function after esp_bt_controller_enable() and before any functions that cause RF transmission, such as performing discovery, profile initialization, and so on.

  2. For BR/EDR to use the new TX power for inquiry, call this function before starting an inquiry. If BR/EDR is already inquiring, restart the inquiry after calling this function.

Parameters

  • min_power_level -- [in] The minimum power level. The default value is ESP_PWR_LVL_N0.

  • max_power_level -- [in] The maximum power level. The default value is ESP_PWR_LVL_P3.

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_ARG: Invalid argument

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

esp_err_t esp_bredr_tx_power_get(esp_power_level_t *min_power_level, esp_power_level_t *max_power_level)

Get BR/EDR TX power.

The corresponding power levels will be stored into the arguments.

Parameters

  • min_power_level -- [out] Pointer to store the minimum power level

  • max_power_level -- [out] The maximum power level

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_ARG: Invalid argument

esp_err_t esp_bredr_sco_datapath_set(esp_sco_data_path_t data_path)

Set default SCO data path.

Note

This function should be called after the Controller is enabled, and before (e)SCO link is established.

Parameters

data_path -- [in] SCO data path

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

esp_err_t esp_bt_controller_init(esp_bt_controller_config_t *cfg)

Initialize the Bluetooth Controller to allocate tasks and other resources.

Note

This function should be called only once, before any other Bluetooth functions.

Parameters

cfg -- [in] Initial Bluetooth Controller configuration

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

esp_err_t esp_bt_controller_deinit(void)

De-initialize Bluetooth Controller to free resources and delete tasks.

Note

  1. You should stop advertising and scanning, and disconnect all existing connections before de-initializing Bluetooth Controller.

  2. This function should be called only once, after any other Bluetooth functions.

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_ARG: Invalid argument

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

  • ESP_ERR_NO_MEM: Out of memory

esp_err_t esp_bt_controller_enable(esp_bt_mode_t mode)

Enable Bluetooth Controller.

For API compatibility, retain this argument. This mode must match the mode specified in the cfg of esp_bt_controller_init().

Note

  1. Bluetooth Controller cannot be enabled in ESP_BT_CONTROLLER_STATUS_IDLE status. It has to be initialized first.

  2. Due to a known issue, you cannot call esp_bt_controller_enable() for the second time to change the Controller mode dynamically. To change the Controller mode, call esp_bt_controller_disable() and then call esp_bt_controller_enable() with the new mode.

Parameters

mode -- [in] The Bluetooth Controller mode (BLE/Classic Bluetooth/BTDM) to enable

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

esp_err_t esp_bt_controller_disable(void)

Disable Bluetooth Controller.

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

esp_bt_controller_status_t esp_bt_controller_get_status(void)

Get Bluetooth Controller status.

Returns

  • ESP_BT_CONTROLLER_STATUS_IDLE: The Controller is not initialized or has been de-initialized.

  • ESP_BT_CONTROLLER_STATUS_INITED: The Controller has been initialized, but not enabled or has been disabled.

  • ESP_BT_CONTROLLER_STATUS_ENABLED: The Controller has been initialized and enabled.

bool esp_vhci_host_check_send_available(void)

Check whether the Controller is ready to receive the packet.

If the return value is True, the Host can send the packet to the Controller.

Note

This function should be called before each esp_vhci_host_send_packet().

Returns

True if the Controller is ready to receive packets; false otherwise

void esp_vhci_host_send_packet(uint8_t *data, uint16_t len)

Send the packet to the Controller.

Note

  1. This function shall not be called within a critical section or when the scheduler is suspended.

  2. This function should be called only if esp_vhci_host_check_send_available() returns True.

Parameters

  • data -- [in] Pointer to the packet data

  • len -- [in] The packet length

esp_err_t esp_vhci_host_register_callback(const esp_vhci_host_callback_t *callback)

Register the VHCI callback funations defined in esp_vhci_host_callback structure.

Parameters

callback -- [in] esp_vhci_host_callback type variable

Returns

  • ESP_OK: Success

  • ESP_FAIL: Failure

esp_err_t esp_bt_controller_mem_release(esp_bt_mode_t mode)

Release the Controller memory as per the mode.

This function releases the BSS, data and other sections of the Controller to heap. The total size is about 70 KB.

If you never intend to use Bluetooth in a current boot-up cycle, calling esp_bt_controller_mem_release(ESP_BT_MODE_BTDM) could release the BSS and data consumed by both Classic Bluetooth and BLE Controller to heap.

If you intend to use BLE only, calling esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT) could release the BSS and data consumed by Classic Bluetooth Controller. You can then continue using BLE.

If you intend to use Classic Bluetooth only, calling esp_bt_controller_mem_release(ESP_BT_MODE_BLE) could release the BSS and data consumed by BLE Controller. You can then continue using Classic Bluetooth.

Note

  1. This function is optional and should be called only if you want to free up memory for other components.

  2. This function should only be called when the controller is in ESP_BT_CONTROLLER_STATUS_IDLE status.

  3. Once Bluetooth Controller memory is released, the process cannot be reversed. This means you cannot use the Bluetooth Controller mode that you have released using this function.

  4. If your firmware will upgrade the Bluetooth Controller mode later (such as switching from BLE to Classic Bluetooth or from disabled to enabled), then do not call this function.

Parameters

mode -- [in] The Bluetooth Controller mode

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

  • ESP_ERR_NOT_FOUND: Requested resource not found

esp_err_t esp_bt_mem_release(esp_bt_mode_t mode)

Release the Controller memory, BSS and data section of the Classic Bluetooth/BLE Host stack as per the mode.

This function first releases Controller memory by internally calling esp_bt_controller_mem_release(), then releases Host memory.

If you never intend to use Bluetooth in a current boot-up cycle, calling esp_bt_mem_release(ESP_BT_MODE_BTDM) could release the BSS and data consumed by both Classic Bluetooth and BLE stack to heap.

If you intend to use BLE only, calling esp_bt_mem_release(ESP_BT_MODE_CLASSIC_BT) could release the BSS and data consumed by Classic Bluetooth. You can then continue using BLE.

If you intend to use Classic Bluetooth only, calling esp_bt_mem_release(ESP_BT_MODE_BLE) could release the BSS and data consumed by BLE. You can then continue using Classic Bluetooth.

For example, if you only use Bluetooth for setting the Wi-Fi configuration, and do not use Bluetooth in the rest of the product operation, after receiving the Wi-Fi configuration, you can disable/de-init Bluetooth and release its memory. Below is the sequence of APIs to be called for such scenarios: 

  esp_bluedroid_disable();
  esp_bluedroid_deinit();
  esp_bt_controller_disable();
  esp_bt_controller_deinit();
  esp_bt_mem_release(ESP_BT_MODE_BTDM);

Note

  1. This function is optional and should be called only if you want to free up memory for other components.

  2. This function should only be called when the controller is in ESP_BT_CONTROLLER_STATUS_IDLE status.

  3. Once Bluetooth Controller memory is released, the process cannot be reversed. This means you cannot use the Bluetooth Controller mode that you have released using this function.

  4. If your firmware will upgrade the Bluetooth Controller mode later (such as switching from BLE to Classic Bluetooth or from disabled to enabled), then do not call this function.

Parameters

mode -- [in] The Bluetooth Controller mode

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

  • ESP_ERR_NOT_FOUND: Requested resource not found

esp_err_t esp_bt_sleep_enable(void)

Enable Bluetooth modem sleep.

There are currently two options for Bluetooth modem sleep: ORIG mode and EVED mode. The latter is intended for BLE only. The modem sleep mode could be configured in menuconfig.

In ORIG mode, if there is no event to process, the Bluetooth Controller will periodically switch off some components and pause operation, then wake up according to the scheduled interval and resume work. It can also wakeup earlier upon external request using function esp_bt_controller_wakeup_request().

Note

This function shall not be invoked before esp_bt_controller_enable().

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

  • ESP_ERR_NOT_SUPPORTED: Operation or feature not supported

esp_err_t esp_bt_sleep_disable(void)

Disable Bluetooth modem sleep.

Note

  1. Bluetooth Controller will not be allowed to enter modem sleep after calling this function.

  2. In ORIG modem sleep mode, calling this function may not immediately wake up the Controller if it is currently dormant. In this case, esp_bt_controller_wakeup_request() can be used to shorten the wake-up time.

  3. This function shall not be invoked before esp_bt_controller_enable().

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

  • ESP_ERR_NOT_SUPPORTED: Operation or feature not supported

esp_err_t esp_ble_scan_duplicate_list_flush(void)

Manually clear the scan duplicate list.

Note

The scan duplicate list will be automatically cleared when the maximum amount of devices in the filter is reached. The amount of devices in the filter can be configured in menuconfig.

Returns

  • ESP_OK: Success

  • ESP_ERR_INVALID_STATE: Invalid Bluetooth Controller state

esp_err_t esp_ble_scan_dupilcate_list_flush(void)

Structures

struct esp_bt_controller_config_t

Bluetooth Controller config options.

Note

  1. For parameters configurable in menuconfig, please refer to menuconfig for details on range and default values.

  2. It is not recommended to modify the default values of controller_task_stack_size and controller_task_prio.

Public Members

uint16_t controller_task_stack_size

Bluetooth Controller task stack size in bytes

uint8_t controller_task_prio

Bluetooth Controller task priority

uint8_t hci_uart_no

Indicates UART number if using UART1/2 as HCI I/O interface. Configurable in menuconfig

uint32_t hci_uart_baudrate

Indicates UART baudrate if using UART1/2 as HCI I/O interface. Configurable in menuconfig

uint8_t scan_duplicate_mode

Scan duplicate filtering mode. Configurable in menuconfig

uint8_t scan_duplicate_type

Scan duplicate filtering type. Configurable in menuconfig

uint16_t normal_adv_size

Maximum number of devices in scan duplicate filtering list. Configurable in menuconfig

uint16_t mesh_adv_size

Maximum number of Mesh advertising packets in scan duplicate filtering list. Configurable in menuconfig

uint16_t send_adv_reserved_size

Controller minimum memory value in bytes. Internal use only

uint32_t controller_debug_flag

Controller debug log flag. Internal use only

uint8_t mode

Controller mode:

1: BLE mode

2: Classic Bluetooth mode

3: Dual mode

Others: Invalid

Configurable in menuconfig

uint8_t ble_max_conn

Maximum number of BLE connections. Configurable in menuconfig

uint8_t bt_max_acl_conn

Maximum number of BR/EDR ACL connections. Configurable in menuconfig

uint8_t bt_sco_datapath

SCO data path, i.e. HCI or PCM module. Configurable in menuconfig

bool auto_latency

True if BLE auto latency is enabled, used to enhance Classic Bluetooth performance; false otherwise. Configurable in menuconfig

bool bt_legacy_auth_vs_evt

True if BR/EDR Legacy Authentication Vendor Specific Event is enabled, which is required to protect from BIAS attack; false otherwise. Configurable in menuconfig

uint8_t bt_max_sync_conn

Maximum number of BR/EDR synchronous connections. Configurable in menuconfig

uint8_t ble_sca

BLE low power crystal accuracy index. Configurable in menuconfig

uint8_t pcm_role

PCM role (master & slave). Configurable in menuconfig

uint8_t pcm_polar

PCM polar trig (falling clk edge & rising clk edge). Configurable in menuconfig

uint8_t pcm_fsyncshp

Physical shape of the PCM Frame Synchronization signal (stereo mode & mono mode). Configurable in menuconfig

bool hli

True if using high level interrupt; false otherwise. Configurable in menuconfig

uint16_t dup_list_refresh_period

Scan duplicate filtering list refresh period in seconds. Configurable in menuconfig

bool ble_scan_backoff

True if BLE scan backoff is enabled; false otherwise. Configurable in menuconfig

uint8_t ble_llcp_disc_flag

BLE disconnect flag when instant passed. Configurable in menuconfig

bool ble_aa_check

True if adds a verification step for the Access Address within the CONNECT_IND PDU; false otherwise. Configurable in menuconfig

uint32_t magic

Magic number

struct esp_vhci_host_callback

Vendor HCI (VHCI) callback functions to notify the Host on the next operation.

Public Members

void (*notify_host_send_available)(void)

Callback to notify the Host that the Controller is ready to receive the packet

int (*notify_host_recv)(uint8_t *data, uint16_t len)

Callback to notify the Host that the Controller has a packet to send

Macros

ESP_BT_CONTROLLER_CONFIG_MAGIC_VAL

Internal use only.

Note

Please do not modify this value

BT_CONTROLLER_INIT_CONFIG_DEFAULT()

Default Bluetooth Controller configuration.

Type Definitions

typedef struct esp_vhci_host_callback esp_vhci_host_callback_t

Vendor HCI (VHCI) callback functions to notify the Host on the next operation.

Enumerations

enum esp_bt_mode_t

Bluetooth Controller mode.

Values:

enumerator ESP_BT_MODE_IDLE

Bluetooth is not operating.

enumerator ESP_BT_MODE_BLE

Bluetooth is operating in BLE mode.

enumerator ESP_BT_MODE_CLASSIC_BT

Bluetooth is operating in Classic Bluetooth mode.

enumerator ESP_BT_MODE_BTDM

Bluetooth is operating in Dual mode.

enum esp_ble_sca_t

BLE sleep clock accuracy (SCA)

Note

Currently only ESP_BLE_SCA_500PPM and ESP_BLE_SCA_250PPM are supported.

Values:

enumerator ESP_BLE_SCA_500PPM

BLE SCA at 500 ppm

enumerator ESP_BLE_SCA_250PPM

BLE SCA at 250 ppm

enumerator ESP_BLE_SCA_150PPM

BLE SCA at 150 ppm

enumerator ESP_BLE_SCA_100PPM

BLE SCA at 100 ppm

enumerator ESP_BLE_SCA_75PPM

BLE SCA at 75 ppm

enumerator ESP_BLE_SCA_50PPM

BLE SCA at 50 ppm

enumerator ESP_BLE_SCA_30PPM

BLE SCA at 30 ppm

enumerator ESP_BLE_SCA_20PPM

BLE SCA at 20 ppm

enum esp_bt_controller_status_t

Bluetooth Controller status.

Values:

enumerator ESP_BT_CONTROLLER_STATUS_IDLE

The Controller is not initialized or has been de-initialized.

enumerator ESP_BT_CONTROLLER_STATUS_INITED

The Controller has been initialized, but not enabled or has been disabled.

enumerator ESP_BT_CONTROLLER_STATUS_ENABLED

The Controller has been initialized and enabled.

enumerator ESP_BT_CONTROLLER_STATUS_NUM

Number of Controller statuses

enum esp_ble_power_type_t

BLE TX power type.

Note

  1. The connection TX power can only be set after the connection is established. After disconnecting, the corresponding TX power will not be affected.

  2. ESP_BLE_PWR_TYPE_DEFAULT can be used to set the TX power for power types that have not been set before. It will not affect the TX power values which have been set for the ADV/SCAN/CONN0-8 power types.

  3. If none of power type is set, the system will use ESP_PWR_LVL_P3 as default for all power types.

Values:

enumerator ESP_BLE_PWR_TYPE_CONN_HDL0

TX power for connection handle 0

enumerator ESP_BLE_PWR_TYPE_CONN_HDL1

TX power for connection handle 1

enumerator ESP_BLE_PWR_TYPE_CONN_HDL2

TX power for connection handle 2

enumerator ESP_BLE_PWR_TYPE_CONN_HDL3

TX power for connection handle 3

enumerator ESP_BLE_PWR_TYPE_CONN_HDL4

TX power for connection handle 4

enumerator ESP_BLE_PWR_TYPE_CONN_HDL5

TX power for connection handle 5

enumerator ESP_BLE_PWR_TYPE_CONN_HDL6

TX power for connection handle 6

enumerator ESP_BLE_PWR_TYPE_CONN_HDL7

TX power for connection handle 7

enumerator ESP_BLE_PWR_TYPE_CONN_HDL8

TX power for connection handle 8

enumerator ESP_BLE_PWR_TYPE_ADV

TX power for advertising

enumerator ESP_BLE_PWR_TYPE_SCAN

TX power for scan

enumerator ESP_BLE_PWR_TYPE_DEFAULT

Default TX power type, which can be used to set the TX power for power types that have not been set before.

enumerator ESP_BLE_PWR_TYPE_NUM

Number of types

enum esp_power_level_t

Bluetooth TX power level (index). Each index corresponds to a specific power value in dBm.

Values:

enumerator ESP_PWR_LVL_N12

Corresponding to -12 dBm

enumerator ESP_PWR_LVL_N9

Corresponding to -9 dBm

enumerator ESP_PWR_LVL_N6

Corresponding to -6 dBm

enumerator ESP_PWR_LVL_N3

Corresponding to -3 dBm

enumerator ESP_PWR_LVL_N0

Corresponding to 0 dBm

enumerator ESP_PWR_LVL_P3

Corresponding to +3 dBm

enumerator ESP_PWR_LVL_P6

Corresponding to +6 dBm

enumerator ESP_PWR_LVL_P9

Corresponding to +9 dBm

enumerator ESP_PWR_LVL_N14

Backward compatibility! Setting to -14 dBm will actually result in -12 dBm

enumerator ESP_PWR_LVL_N11

Backward compatibility! Setting to -11 dBm will actually result in -9 dBm

enumerator ESP_PWR_LVL_N8

Backward compatibility! Setting to -8 dBm will actually result in -6 dBm

enumerator ESP_PWR_LVL_N5

Backward compatibility! Setting to -5 dBm will actually result in -3 dBm

enumerator ESP_PWR_LVL_N2

Backward compatibility! Setting to -2 dBm will actually result in 0 dBm

enumerator ESP_PWR_LVL_P1

Backward compatibility! Setting to +1 dBm will actually result in +3 dBm

enumerator ESP_PWR_LVL_P4

Backward compatibility! Setting to +4 dBm will actually result in +6 dBm

enumerator ESP_PWR_LVL_P7

Backward compatibility! Setting to +7 dBm will actually result in +9 dBm

enum esp_sco_data_path_t

Bluetooth audio data transport path.

Values:

enumerator ESP_SCO_DATA_PATH_HCI

data over HCI transport

enumerator ESP_SCO_DATA_PATH_PCM

data over PCM interface

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