Controller && VHCI

Application Example

Check bluetooth/hci folder in ESP-IDF examples, which contains the following application:

This is a Bluetooth® Low Energy (Bluetooth LE) advertising demo with virtual HCI interface. Send Reset/ADV_PARAM/ADV_DATA/ADV_ENABLE HCI command for Bluetooth Low Energy advertising - bluetooth/hci/controller_vhci_ble_adv.

API Reference

Header File

components/bt/include/esp32c3/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 Connection Tx power should only be set after connection created.

Parameters

power_type -- : The type of which tx power, could set Advertising/Connection/Default and etc
power_level -- Power level(index) corresponding to absolute value(dbm)

Returns

ESP_OK - success, other - failed

esp_power_level_t esp_ble_tx_power_get(esp_ble_power_type_t power_type)

Get BLE TX power Connection Tx power should only be get after connection created.

Parameters: power_type -- : The type of which tx power, could set Advertising/Connection/Default and etc
Returns: >= 0 - Power level, < 0 - Invalid

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_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

esp_bt_controller_status_t esp_bt_controller_get_status(void)

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

Returns: status value

uint16_t esp_bt_get_tx_buf_num(void)

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

esp_err_t esp_bt_sleep_enable(void)

enable bluetooth to enter modem sleep

Note that this function shall not be invoked before esp_bt_controller_enable()

There are currently two options for bluetooth modem sleep, one is ORIG mode, and another is EVED Mode. EVED Mode is intended for BLE only.

For ORIG mode: Bluetooth modem sleep is enabled in controller start up by default if CONFIG_BTDM_CONTROLLER_MODEM_SLEEP is set and "ORIG mode" is selected. In ORIG modem sleep mode, bluetooth controller will switch off some components and pause to work every now and then, if there is no event to process; and wakeup according to the scheduled interval and resume the work. It can also wakeup earlier upon external request using function "esp_bt_controller_wakeup_request".

Returns

ESP_OK : success
other : failed

esp_err_t esp_bt_sleep_disable(void)

disable bluetooth modem sleep

Note that this function shall not be invoked before esp_bt_controller_enable()

If esp_bt_sleep_disable() is called, bluetooth controller will not be allowed to enter modem sleep;

If ORIG modem sleep mode is in use, if this function is called, bluetooth controller may not immediately wake up if it is dormant then. In this case, esp_bt_controller_wakeup_request() can be used to shorten the time for wakeup.

Returns

ESP_OK : success
other : failed

bool esp_bt_controller_is_sleeping(void)

to check whether bluetooth controller is sleeping at the instant, if modem sleep is enabled

Note that this function shall not be invoked before esp_bt_controller_enable() This function is supposed to be used ORIG mode of modem sleep

Returns: true if in modem sleep state, false otherwise

void esp_bt_controller_wakeup_request(void)

request controller to wakeup from sleeping state during sleep mode

Note that this function shall not be invoked before esp_bt_controller_enable() Note that this function is supposed to be used ORIG mode of modem sleep Note that after this request, bluetooth controller may again enter sleep as long as the modem sleep is enabled

Profiling shows that it takes several milliseconds to wakeup from modem sleep after this request. Generally it takes longer if 32kHz XTAL is used than the main XTAL, due to the lower frequency of the former as the bluetooth low power clock source.

int esp_bt_h4tl_eif_io_event_notify(int event)

notify bluetooth controller task to process the event upon Tx or Rx done

Note that this function shall not be invoked before esp_bt_controller_enable() This function can be called in both ISR and non-ISR context

void esp_wifi_bt_power_domain_on(void): bt Wi-Fi power domain power on

void esp_wifi_bt_power_domain_off(void): bt Wi-Fi power domain power off

Structures

struct esp_bt_hci_tl_t

Controller HCI transport layer function structure This structure shall be registered when HCI transport layer is UART.

Public Members

uint32_t _magic: Magic number

uint32_t _version: Version number of the defined structure

uint32_t _reserved: Reserved for future use

int (*_open)(void): HCI transport layer open function

void (*_close)(void): HCI transport layer close function

void (*_finish_transfers)(void): HCI transport layer finish transfers function

void (*_recv)(uint8_t *buf, uint32_t len, esp_bt_hci_tl_callback_t callback, void *arg): HCI transport layer receive function

void (*_send)(uint8_t *buf, uint32_t len, esp_bt_hci_tl_callback_t callback, void *arg): HCI transport layer send function

bool (*_flow_off)(void): HCI transport layer flow off function

void (*_flow_on)(void): HCI transport layer flow on function

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

uint32_t magic: Magic number

uint32_t version: version number of the defined structure

uint16_t controller_task_stack_size: Bluetooth controller task stack size

uint8_t controller_task_prio: Bluetooth controller task priority

uint8_t controller_task_run_cpu: CPU num that Bluetooth controller task runs on

uint8_t bluetooth_mode: Controller mode: BR/EDR, BLE or Dual Mode

uint8_t ble_max_act: BLE maximum number of air activities

uint8_t sleep_mode: controller sleep mode

uint8_t sleep_clock: controller sleep clock

uint8_t ble_st_acl_tx_buf_nb: controller static ACL TX BUFFER number

uint8_t ble_hw_cca_check: controller hardware triggered CCA check

uint16_t ble_adv_dup_filt_max: maxinum number of duplicate scan filter

bool coex_param_en: deprecated

uint8_t ce_len_type: connection event length computation method

bool coex_use_hooks: deprecated

uint8_t hci_tl_type: HCI transport layer, UART, VHCI, etc

esp_bt_hci_tl_t *hci_tl_funcs: hci transport functions used, must be set when hci_tl_type is UART

uint8_t txant_dft: default Tx antenna

uint8_t rxant_dft: default Rx antenna

uint8_t txpwr_dft: default Tx power

uint32_t cfg_mask: Configuration mask to set specific options

uint8_t scan_duplicate_mode: scan duplicate mode

uint8_t scan_duplicate_type: scan duplicate type

uint16_t normal_adv_size: Normal adv size for scan duplicate

uint16_t mesh_adv_size: Mesh adv size for scan duplicate

uint8_t coex_phy_coded_tx_rx_time_limit: limit on max tx/rx time in case of connection using CODED-PHY with Wi-Fi coexistence

uint32_t hw_target_code: hardware target

uint8_t slave_ce_len_min: slave minimum ce length

uint8_t hw_recorrect_en: Hardware re-correction enabled

uint8_t cca_thresh: cca threshold

uint16_t scan_backoff_upperlimitmax: scan backoff upperlimitmax value

uint16_t dup_list_refresh_period: duplicate scan list refresh time

bool ble_50_feat_supp: BLE 5.0 feature support

uint8_t ble_cca_mode: BLE CCA mode

uint8_t ble_data_lenth_zero_aux: Config ext adv aux option

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

ESP_BT_CTRL_CONFIG_MAGIC_VAL

ESP_BT_CTRL_CONFIG_VERSION

ESP_BT_HCI_TL_MAGIC_VALUE

ESP_BT_HCI_TL_VERSION

ESP_BT_HCI_TL_STATUS_OK: HCI_TL Tx/Rx operation status OK

BT_CONTROLLER_INIT_CONFIG_DEFAULT()

Type Definitions

typedef void (*esp_bt_hci_tl_callback_t)(void *arg, uint8_t status): callback function for HCI Transport Layer send/receive operations

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_ctrl_hci_tl_t

Type of controller HCI transport layer.

Values:

enumerator ESP_BT_CTRL_HCI_TL_UART: HCI UART h4 transport layer

enumerator ESP_BT_CTRL_HCI_TL_VHCI: VHCI interface

enum esp_ble_ce_len_t

type of BLE connection event length computation

Values:

enumerator ESP_BLE_CE_LEN_TYPE_ORIG: original

enumerator ESP_BLE_CE_LEN_TYPE_CE: use CE_LEN parameter from HCI commands

enumerator ESP_BLE_CE_LEN_TYPE_SD: Espressif vendor defined

enum esp_bt_sleep_mode_t

Bluetooth sleep mode.

Values:

enumerator ESP_BT_SLEEP_MODE_NONE: Bluetooth sleep mode disabled

enumerator ESP_BT_SLEEP_MODE_1: Bluetooth sleep mode 1

enum esp_bt_sleep_clock_t

Bluetooth sleep clock.

Values:

enumerator ESP_BT_SLEEP_CLOCK_NONE: Sleep clock not configured

enumerator ESP_BT_SLEEP_CLOCK_MAIN_XTAL: SoC main crystal

enumerator ESP_BT_SLEEP_CLOCK_EXT_32K_XTAL: External 32.768kHz crystal

enumerator ESP_BT_SLEEP_CLOCK_RTC_SLOW: Internal 136kHz RC oscillator

enumerator ESP_BT_SLEEP_CLOCK_FPGA_32K: Hardwired 32KHz clock temporarily used for FPGA

enum [anonymous]

antenna index used for bluetooth

Values:

enumerator ESP_BT_ANT_IDX_0: anntena NO 0

enumerator ESP_BT_ANT_IDX_1: anntena NO 1

enum [anonymous]

Maximum Tx/Rx time limit on Coded-PHY connection.

Values:

enumerator ESP_BT_COEX_PHY_CODED_TX_RX_TIME_LIMIT_FORCE_DISABLE: Disable the limit

enumerator ESP_BT_COEX_PHY_CODED_TX_RX_TIME_LIMIT_FORCE_ENABLE: Always Enable the limit

enum esp_bt_controller_status_t

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

Values:

enumerator ESP_BT_CONTROLLER_STATUS_IDLE

enumerator ESP_BT_CONTROLLER_STATUS_INITED

enumerator ESP_BT_CONTROLLER_STATUS_ENABLED

enumerator ESP_BT_CONTROLLER_STATUS_NUM

enum esp_ble_power_type_t

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_t

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_P18: Corresponding to +18dbm

enumerator ESP_PWR_LVL_P21: Corresponding to +21dbm

enumerator ESP_PWR_LVL_INVALID: Indicates an invalid value

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