esp-idf/examples/bluetooth/bluedroid/bluedroid_host_only/bluedroid_host_only_uart

Supported Targets	ESP32	ESP32-C2	ESP32-C3	ESP32-C6	ESP32-H2	ESP32-S3

ESP-IDF UART HCI Host

This is a Bluetooth Host use UART as HCI IO. This require the UART device support RTS/CTS mandatory.

It can do the configuration of UART baudrate by menuconfig.

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 uart driver: uart_driver.c and uart_driver.h.

• Initialize UART driver in main.c.

#include "esp_hci_api.h"
#include "uart_driver.h"

...

/* initialize HCI TRANSPORT first */
hci_uart_open();
/* get HCI driver operations */
esp_bluedroid_hci_driver_operations_t operations = {
    .send = hci_uart_send,
    .check_send_available = hci_check_send_available,
    .register_host_callback = hci_register_host_callback,
};
esp_bluedroid_attach_hci_driver(&operations);

How to use example

Hardware Required

This example should be able to run on any commonly available ESP development board. To connect UART to another board running a Bluetooth controller. For example, controller_hci_uart_esp32.

Configure the project

idf.py menuconfig

• UART baudrate can be configured in Example Configuration > UART Baudrate for HCI

Build and Flash

Build the project and flash it to the board, then run monitor tool to view serial output:

idf.py -p PORT flash monitor

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

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

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Troubleshooting