ESP-IDF ESP-Hosted Hosted HCI Host

This is a Bluetooth Host using ESP-Hosted as HCI IO to the BT Controller.

Example Layout

This example is modified based on bt_discovery, and all modifications are listed below:

• Removed all dependencies on controller from main.c.

#include "esp_bt.h"

...

ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_BLE));

esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
if ((ret = esp_bt_controller_init(&bt_cfg)) != ESP_OK) {
    ESP_LOGE(GAP_TAG, "%s initialize controller failed: %s", __func__, esp_err_to_name(ret));
    return;
}

if ((ret = esp_bt_controller_enable(ESP_BT_MODE_CLASSIC_BT)) != ESP_OK) {
    ESP_LOGE(GAP_TAG, "%s enable controller failed: %s", __func__, esp_err_to_name(ret));
    return;
}

• Add support for ESP-Hosted HCI interface: esp_hosted_bt.h.

• Open HCI interface in main.c.

#include "esp_hosted_bt.h"

...

/* initialize TRANSPORT first */
hosted_hci_bluedroid_open();

/* get HCI driver operations */
esp_bluedroid_hci_driver_operations_t operations = {
    .send = hosted_hci_bluedroid_uart_send,
    .check_send_available = hosted_hci_bluedroid_check_send_available,
    .register_host_callback = hosted_hci_bluedroid_register_host_callback,
};
esp_bluedroid_attach_hci_driver(&operations);

How to use example

Hardware Required

This example runs on the ESP32-P4 Dev Board connected to a ESP32 via the GPIO header, using SPI FD (full duplex) as Hosted HCI transport. The following GPIO settings were used:

Users are free to choose which supported ESP-Hosted transport to use. See the main ESP-Hosted README for a list of supported transports.

For standard HCI, configure the co-processor Bluetooth Controller to use UART as the HCI transport, then select appropriate GPIOs on the ESP32-P4 to configure as a UART. In this mode, ESP-Hosted is not involved in transporting the HCI data.

See the ESP-IDF UART HCI Host example on how to set-up UART for the Bluetooth Host.

Configure the project

For the ESP32 co-processor, run idf.py menuconfig and configure Example Configuration for SPI Full-duplex with the correct SPI mode and GPIOs.

For the ESP32-P4 co-processor, run idf.py menuconfig and under Component config ---> ESP-Hosted config:

• set the transport to be SPI Full-duplex with the correct SPI modem GPIOs (see above table) and SPI Clock frequency (10 MHz max).
• set the Slave chipset used as ESP32.
• set Bluetooth Support ---> Enable Hosted Bluedroid Bluetooth support to enable Bluedroid support. Leave the HCI type as VHCI.

Build and Flash

Build and flash the co-processor and host projects, then run monitor tool to view serial output on both the ESP32 and ESP32-P4:

idf.py -p PORT flash monitor

(Replace PORT with the name of the serial port to use.)

(To exit the serial monitor, type Ctrl-].)