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Controller & HCI

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API Reference

Header File

  • components/bt/include/esp32h4/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_bt_controller_init(esp_bt_controller_config_t *cfg)

Initialize BT controller to allocate task and other resource. This function should be called only once, before any other BT functions are called.

Parameters:

cfg -- Initial configuration of BT controller. Different from previous version, there's a mode and some connection configuration in "cfg" to configure controller work mode and allocate the resource which is needed.

Returns:

ESP_OK - success, other - failed

esp_bt_controller_status_t esp_bt_controller_get_status(void)

Get BT controller is initialised/de-initialised/enabled/disabled.

Returns:

status value

esp_err_t esp_bt_controller_deinit(void)

De-initialize BT controller to free resource and delete task. You should stop advertising and scanning, as well as disconnect all existing connections before de-initializing BT controller.

This function should be called only once, after any other BT functions are called. This function is not whole completed, esp_bt_controller_init cannot called after this function.

Returns:

ESP_OK - success, other - failed

esp_err_t esp_bt_controller_enable(esp_bt_mode_t mode)

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

Parameters:

mode -- : the mode(BLE/BT/BTDM) to enable. For compatible of API, retain this argument. This mode must be equal as the mode in "cfg" of esp_bt_controller_init().

Returns:

ESP_OK - success, other - failed

esp_err_t esp_bt_controller_disable(void)

Disable BT controller.

Returns:

ESP_OK - success, other - failed

bool esp_vhci_host_check_send_available(void)

esp_vhci_host_check_send_available used for check actively if the host can send packet to controller or not.

Returns:

true for ready to send, false means cannot send packet

void esp_vhci_host_send_packet(uint8_t *data, uint16_t len)

esp_vhci_host_send_packet host send packet to controller

Should not call this function from within a critical section or when the scheduler is suspended.

Parameters:

  • data -- the packet point

  • len -- the packet length

esp_err_t esp_vhci_host_register_callback(const esp_vhci_host_callback_t *callback)

esp_vhci_host_register_callback register the vhci reference callback struct defined by vhci_host_callback structure.

Parameters:

callback -- esp_vhci_host_callback type variable

Returns:

ESP_OK - success, ESP_FAIL - failed

esp_err_t esp_bt_controller_mem_release(esp_bt_mode_t mode)

esp_bt_controller_mem_release 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 70k bytes.

esp_bt_controller_mem_release(mode) should be called only before esp_bt_controller_init() or after esp_bt_controller_deinit().

Note that once BT controller memory is released, the process cannot be reversed. It means you cannot use the bluetooth mode which you have released by this function.

If your firmware will later upgrade the Bluetooth controller mode (BLE -> BT Classic or disabled -> enabled) then do not call this function.

If the app calls esp_bt_controller_enable(ESP_BT_MODE_BLE) to use BLE only then it is safe to call esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT) at initialization time to free unused BT Classic memory.

If the mode is ESP_BT_MODE_BTDM, then it may be useful to call API esp_bt_mem_release(ESP_BT_MODE_BTDM) instead, which internally calls esp_bt_controller_mem_release(ESP_BT_MODE_BTDM) and additionally releases the BSS and data consumed by the BT/BLE host stack to heap. For more details about usage please refer to the documentation of esp_bt_mem_release() function

Parameters:

mode -- : the mode want to release memory

Returns:

ESP_OK - success, other - failed

esp_err_t esp_bt_mem_release(esp_bt_mode_t mode)

esp_bt_mem_release release controller memory and BSS and data section of the BT/BLE host stack as per the mode

This function first releases controller memory by internally calling esp_bt_controller_mem_release(). Additionally, if the mode is set to ESP_BT_MODE_BTDM, it also releases the BSS and data consumed by the BT/BLE host stack to heap

Note that once BT memory is released, the process cannot be reversed. It means you cannot use the bluetooth mode which you have released by this function.

If your firmware will later upgrade the Bluetooth controller mode (BLE -> BT Classic or disabled -> enabled) then do not call this function.

If you never intend to use bluetooth in a current boot-up cycle, you can call esp_bt_mem_release(ESP_BT_MODE_BTDM) before esp_bt_controller_init or after esp_bt_controller_deinit.

For example, if a user only uses bluetooth for setting the WiFi configuration, and does not use bluetooth in the rest of the product operation". In such cases, after receiving the WiFi configuration, you can disable/deinit 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);

Parameters:

mode -- : the mode whose memory is to be released

Returns:

ESP_OK - success, other - failed

int esp_ble_hw_get_static_addr(esp_ble_addr_t *addr)

Returns random static address or -1 if not present.

Returns:

ESP_OK - success, other - failed

Structures

struct esp_ble_addr_t

Address type and address value.

Public Members

uint8_t type

Type of the Bluetooth address (public, random, etc.)

uint8_t val[6]

Array containing the 6-byte Bluetooth address value

struct esp_bt_ctrl_btdm_config_t

BTDM controller common configuration options.

Public Members

uint32_t version

Version number of the defined structure

uint16_t task_stack_size

Size of Bluetooth controller task stack

uint8_t task_prio

Priority of the Bluetooth controller task

uint8_t task_run_cpu

CPU number on which the Bluetooth controller task runs

uint8_t hci_cmd_num

HCI command buffer number

uint8_t sleep_en

Enable sleep functionality

uint8_t version_num

Hardware version number of this chip

uint8_t bluetooth_mode

Controller mode: BR/EDR, BLE or Dual Mode

uint32_t magic

Magic number for configuration validation

struct esp_bt_controller_config_t

Controller config options, depend on config mask. Config mask indicate which functions enabled, this means some options or parameters of some functions enabled by config mask.

Public Members

esp_bt_ctrl_le_config_t ble

Bluetooth LE controller configuration options

esp_bt_ctrl_btdm_config_t btdm

Bluetooth controller common configuration options

struct esp_vhci_host_callback

esp_vhci_host_callback used for vhci call host function to notify what host need to do

Public Members

void (*notify_host_send_available)(void)

callback used to notify that the host can send packet to controller

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

callback used to notify that the controller has a packet to send to the host

Macros

BTDM_CONFIG_VERSION
BTDM_CONFIG_MAGIC_VALUE
BTDM_CONTROLLER_MODE_EFF
BT_CONTROLLER_INIT_CONFIG_DEFAULT()

Type Definitions

typedef enum esp_ble_power_type esp_ble_power_type_t
typedef enum esp_power_level esp_power_level_t
typedef struct esp_vhci_host_callback esp_vhci_host_callback_t

esp_vhci_host_callback used for vhci call host function to notify what host need to do

Enumerations

enum esp_bt_mode_t

Bluetooth mode for controller enable/disable.

Values:

enumerator ESP_BT_MODE_IDLE

Bluetooth is not running

enumerator ESP_BT_MODE_BLE

Run BLE mode

enumerator ESP_BT_MODE_CLASSIC_BT

Run Classic BT mode

enumerator ESP_BT_MODE_BTDM

Run dual mode

enum esp_bt_controller_status_t

Bluetooth controller enable/disable/initialised/de-initialised status.

Values:

enumerator ESP_BT_CONTROLLER_STATUS_IDLE

Controller is in idle state

enumerator ESP_BT_CONTROLLER_STATUS_INITED

Controller is in initialising state

enumerator ESP_BT_CONTROLLER_STATUS_ENABLED

Controller is in enabled state

enumerator ESP_BT_CONTROLLER_STATUS_NUM

Controller is in disabled state

enum esp_ble_power_type

BLE tx power type ESP_BLE_PWR_TYPE_CONN_HDL0-8: for each connection, and only be set after connection completed. when disconnect, the correspond TX power is not effected. ESP_BLE_PWR_TYPE_ADV : for advertising/scan response. ESP_BLE_PWR_TYPE_SCAN : for scan. ESP_BLE_PWR_TYPE_DEFAULT : if each connection's TX power is not set, it will use this default value. if neither in scan mode nor in adv mode, it will use this default value. If none of power type is set, system will use ESP_PWR_LVL_P3 as default for ADV/SCAN/CONN0-9.

Values:

enumerator ESP_BLE_PWR_TYPE_CONN_HDL0

For connection handle 0

enumerator ESP_BLE_PWR_TYPE_CONN_HDL1

For connection handle 1

enumerator ESP_BLE_PWR_TYPE_CONN_HDL2

For connection handle 2

enumerator ESP_BLE_PWR_TYPE_CONN_HDL3

For connection handle 3

enumerator ESP_BLE_PWR_TYPE_CONN_HDL4

For connection handle 4

enumerator ESP_BLE_PWR_TYPE_CONN_HDL5

For connection handle 5

enumerator ESP_BLE_PWR_TYPE_CONN_HDL6

For connection handle 6

enumerator ESP_BLE_PWR_TYPE_CONN_HDL7

For connection handle 7

enumerator ESP_BLE_PWR_TYPE_CONN_HDL8

For connection handle 8

enumerator ESP_BLE_PWR_TYPE_ADV

For advertising

enumerator ESP_BLE_PWR_TYPE_SCAN

For scan

enumerator ESP_BLE_PWR_TYPE_DEFAULT

For default, if not set other, it will use default value

enumerator ESP_BLE_PWR_TYPE_NUM

TYPE numbers

enum esp_power_level

Bluetooth TX power level(index), it's just a index corresponding to power(dbm).

Values:

enumerator ESP_PWR_LVL_N24

Corresponding to -24dbm

enumerator ESP_PWR_LVL_N21

Corresponding to -21dbm

enumerator ESP_PWR_LVL_N18

Corresponding to -18dbm

enumerator ESP_PWR_LVL_N15

Corresponding to -15dbm

enumerator ESP_PWR_LVL_N12

Corresponding to -12dbm

enumerator ESP_PWR_LVL_N9

Corresponding to -9dbm

enumerator ESP_PWR_LVL_N6

Corresponding to -6dbm

enumerator ESP_PWR_LVL_N3

Corresponding to -3dbm

enumerator ESP_PWR_LVL_N0

Corresponding to 0dbm

enumerator ESP_PWR_LVL_P3

Corresponding to +3dbm

enumerator ESP_PWR_LVL_P6

Corresponding to +6dbm

enumerator ESP_PWR_LVL_P9

Corresponding to +9dbm

enumerator ESP_PWR_LVL_P12

Corresponding to +12dbm

enumerator ESP_PWR_LVL_P15

Corresponding to +15dbm

enumerator ESP_PWR_LVL_P16

Corresponding to +16dbm

enumerator ESP_PWR_LVL_P17

Corresponding to +17dbm

enumerator ESP_PWR_LVL_P18

Corresponding to +18dbm

enumerator ESP_PWR_LVL_P19

Corresponding to +19dbm

enumerator ESP_PWR_LVL_P20

Corresponding to +20dbm

enumerator ESP_PWR_LVL_INVALID

Indicates an invalid value

HCI Vendor-specific (VS) Commands

Espressif's HCI VS commands are exclusively designed for use with Espressif's Bluetooth Host stack or internal debugging purposes. Application developers should not initialize or invoke these VS commands in their applications. Please refer to HCI Vendor-specific (VS) Commands for detailed information.

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