esp-idf BLE gatt creating multiple characteristics

Thread Starter

zazas321

Joined Nov 29, 2015
917
Hello. I am programming ESP32 device and cannot figure out how can I create multiple characteristics for a single BLE service. My full code:
Code:
/*
   This example code is in the Public Domain (or CC0 licensed, at your option.)
   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/
/****************************************************************************
*
* This demo showcases BLE GATT server. It can send adv data, be connected by client.
* Run the gatt_client demo, the client demo will automatically connect to the gatt_server demo.
* Client demo will enable gatt_server's notify after connection. The two devices will then exchange
* data.
*
****************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "esp_system.h"
#include "esp_log.h"

//#include "BLE_custom.h"
#include "esp_bt.h"
#include "esp_gap_ble_api.h"
#include "esp_gatts_api.h"
#include "esp_bt_defs.h"
#include "esp_bt_main.h"
#include "esp_gatt_common_api.h"
//#include "sdkconfig.h"

static void gatts_profile_a_event_handler(esp_gatts_cb_event_t event, esp_gatt_if_t gatts_if, esp_ble_gatts_cb_param_t *param);
static void gap_event_handler(esp_gap_ble_cb_event_t event, esp_ble_gap_cb_param_t *param);
static void gatts_event_handler(esp_gatts_cb_event_t event, esp_gatt_if_t gatts_if, esp_ble_gatts_cb_param_t *param);


///Declare the static function




// change this to normal struct not typedef
typedef struct {
    uint8_t                 *prepare_buf;
    int                     prepare_len;
} prepare_type_env_t;



#define GATTS_SERVICE_UUID   0x00FF
#define GATTS_CHAR1_UUID     0xFF01
#define GATTS_CHAR2_UUID     0xFF02
#define GATTS_DESCR_UUID_TEST_A     0x3333
#define GATTS_NUM_HANDLE_TEST_A     4


#define TEST_DEVICE_NAME            "ESP_GATTS_DEMO"
#define TEST_MANUFACTURER_DATA_LEN  17
#define GATTS_DEMO_CHAR_VAL_LEN_MAX 0x40
#define PREPARE_BUF_MAX_SIZE 1024
#define GATTS_TAG "GATTS_DEMO"






static uint8_t char1_str[] = "test";
static esp_gatt_char_prop_t a_property = 0;
static esp_gatt_char_prop_t a2_property = 0;

static esp_attr_value_t gatts_demo_char1_val =
{
    .attr_max_len = GATTS_DEMO_CHAR_VAL_LEN_MAX,
    .attr_len     = sizeof(char1_str),
    .attr_value   = char1_str,
};
static uint8_t adv_config_done = 0;
#define adv_config_flag      (1 << 0)
#define scan_rsp_config_flag (1 << 1)
#ifdef CONFIG_SET_RAW_ADV_DATA
static uint8_t raw_adv_data[] = {
        0x02, 0x01, 0x06,
        0x02, 0x0a, 0xeb, 0x03, 0x03, 0xab, 0xcd
};
static uint8_t raw_scan_rsp_data[] = {
        0x0f, 0x09, 0x45, 0x53, 0x50, 0x5f, 0x47, 0x41, 0x54, 0x54, 0x53, 0x5f, 0x44,
        0x45, 0x4d, 0x4f
};
#else
static uint8_t Fadv_service_uuid128[32] = {
    /* LSB <--------------------------------------------------------------------------------> MSB */
    //first uuid, 16bit, [12],[13] is the value
    0xfb, 0x34, 0x9b, 0x5f, 0x80, 0x00, 0x00, 0x80, 0x00, 0x10, 0x00, 0x00, 0xEE, 0x00, 0x00, 0x00,
    //second uuid, 32bit, [12], [13], [14], [15] is the value
    0xfb, 0x34, 0x9b, 0x5f, 0x80, 0x00, 0x00, 0x80, 0x00, 0x10, 0x00, 0x00, 0xFF, 0x00, 0x00, 0x00,
};
// The length of adv data must be less than 31 bytes
//static uint8_t test_manufacturer[TEST_MANUFACTURER_DATA_LEN] =  {0x12, 0x23, 0x45, 0x56};
//adv data
static esp_ble_adv_data_t adv_data = {
    .set_scan_rsp = false,
    .include_name = true,
    .include_txpower = false,
    .min_interval = 0x0006, //slave connection min interval, Time = min_interval * 1.25 msec
    .max_interval = 0x0010, //slave connection max interval, Time = max_interval * 1.25 msec
    .appearance = 0x00,
    .manufacturer_len = 0, //TEST_MANUFACTURER_DATA_LEN,
    .p_manufacturer_data =  NULL, //&test_manufacturer[0],
    .service_data_len = 0,
    .p_service_data = NULL,
    .service_uuid_len = sizeof(adv_service_uuid128),
    .p_service_uuid = adv_service_uuid128,
    .flag = (ESP_BLE_ADV_FLAG_GEN_DISC | ESP_BLE_ADV_FLAG_BREDR_NOT_SPT),
};
// scan response data
static esp_ble_adv_data_t scan_rsp_data = {
    .set_scan_rsp = true,
    .include_name = true,
    .include_txpower = true,
    //.min_interval = 0x0006,
    //.max_interval = 0x0010,
    .appearance = 0x00,
    .manufacturer_len = 0, //TEST_MANUFACTURER_DATA_LEN,
    .p_manufacturer_data =  NULL, //&test_manufacturer[0],
    .service_data_len = 0,
    .p_service_data = NULL,
    .service_uuid_len = sizeof(adv_service_uuid128),
    .p_service_uuid = adv_service_uuid128,
    .flag = (ESP_BLE_ADV_FLAG_GEN_DISC | ESP_BLE_ADV_FLAG_BREDR_NOT_SPT),
};
#endif /* CONFIG_SET_RAW_ADV_DATA */
static esp_ble_adv_params_t adv_params = {
    .adv_int_min        = 0x20,
    .adv_int_max        = 0x40,
    .adv_type           = ADV_TYPE_IND,
    .own_addr_type      = BLE_ADDR_TYPE_PUBLIC,
    //.peer_addr            =
    //.peer_addr_type       =
    .channel_map        = ADV_CHNL_ALL,
    .adv_filter_policy = ADV_FILTER_ALLOW_SCAN_ANY_CON_ANY,
};
#define PROFILE_NUM 1
#define PROFILE_A_APP_ID 0

struct gatts_profile_inst {
    esp_gatts_cb_t gatts_cb;
    uint16_t gatts_if;
    uint16_t app_id;
    uint16_t conn_id;
    uint16_t service_handle;
    esp_gatt_srvc_id_t service_id;
    uint16_t char_handle;
    esp_bt_uuid_t char_uuid;
    esp_gatt_perm_t perm;
    esp_gatt_char_prop_t property;
    uint16_t descr_handle;
    esp_bt_uuid_t descr_uuid;
};
/* One gatt-based profile one app_id and one gatts_if, this array will store the gatts_if returned by ESP_GATTS_REG_EVT */
static struct gatts_profile_inst gl_profile_tab[PROFILE_NUM] = {
    [PROFILE_A_APP_ID] = {
        .gatts_cb = gatts_profile_a_event_handler,
        .gatts_if = ESP_GATT_IF_NONE,       /* Not get the gatt_if, so initial is ESP_GATT_IF_NONE */
    },
};

static prepare_type_env_t a_prepare_write_env;



static void gap_event_handler(esp_gap_ble_cb_event_t event, esp_ble_gap_cb_param_t *param)
{
    switch (event) {
#ifdef CONFIG_SET_RAW_ADV_DATA
    case ESP_GAP_BLE_ADV_DATA_RAW_SET_COMPLETE_EVT:
        adv_config_done &= (~adv_config_flag);
        if (adv_config_done==0){
            esp_ble_gap_start_advertising(&adv_params);
        }
        break;
    case ESP_GAP_BLE_SCAN_RSP_DATA_RAW_SET_COMPLETE_EVT:
        adv_config_done &= (~scan_rsp_config_flag);
        if (adv_config_done==0){
            esp_ble_gap_start_advertising(&adv_params);
        }
        break;
#else
    case ESP_GAP_BLE_ADV_DATA_SET_COMPLETE_EVT:
        printf("ESP_GAP_BLE_ADV_DATA_SET_COMPLETE_EVT\n");
        adv_config_done &= (~adv_config_flag);
        if (adv_config_done == 0){
            esp_ble_gap_start_advertising(&adv_params);
        }
        break;
    case ESP_GAP_BLE_SCAN_RSP_DATA_SET_COMPLETE_EVT:
        printf("ESP_GAP_BLE_SCAN_RSP_DATA_SET_COMPLETE_EVT\n");
        adv_config_done &= (~scan_rsp_config_flag);
        if (adv_config_done == 0){
            esp_ble_gap_start_advertising(&adv_params);
        }
        break;
#endif
    case ESP_GAP_BLE_ADV_START_COMPLETE_EVT:
    printf("ESP_GAP_BLE_ADV_START_COMPLETE_EVT\n");
        //advertising start complete event to indicate advertising start successfully or failed
        if (param->adv_start_cmpl.status != ESP_BT_STATUS_SUCCESS) {
            ESP_LOGE(GATTS_TAG, "Advertising start failed\n");
        }
        break;
    case ESP_GAP_BLE_ADV_STOP_COMPLETE_EVT:
    printf("ESP_GAP_BLE_ADV_STOP_COMPLETE_EVT\n");
        if (param->adv_stop_cmpl.status != ESP_BT_STATUS_SUCCESS) {
            ESP_LOGE(GATTS_TAG, "Advertising stop failed\n");
        } else {
            ESP_LOGI(GATTS_TAG, "Stop adv successfully\n");
        }
        break;
    case ESP_GAP_BLE_UPDATE_CONN_PARAMS_EVT:
    printf("ESP_GAP_BLE_UPDATE_CONN_PARAMS_EVT");
         ESP_LOGI(GATTS_TAG, "update connection params status = %d, min_int = %d, max_int = %d,conn_int = %d,latency = %d, timeout = %d",
                  param->update_conn_params.status,
                  param->update_conn_params.min_int,
                  param->update_conn_params.max_int,
                  param->update_conn_params.conn_int,
                  param->update_conn_params.latency,
                  param->update_conn_params.timeout);
        break;
    default:
        break;
    }
}
void example_write_event_env(esp_gatt_if_t gatts_if, prepare_type_env_t *prepare_write_env, esp_ble_gatts_cb_param_t *param){
    printf("example_write_event_env\n");
    esp_gatt_status_t status = ESP_GATT_OK;
    if (param->write.need_rsp){
        if (param->write.is_prep){
            if (prepare_write_env->prepare_buf == NULL) {
                prepare_write_env->prepare_buf = (uint8_t *)malloc(PREPARE_BUF_MAX_SIZE*sizeof(uint8_t));
                prepare_write_env->prepare_len = 0;
                if (prepare_write_env->prepare_buf == NULL) {
                    ESP_LOGE(GATTS_TAG, "Gatt_server prep no mem\n");
                    status = ESP_GATT_NO_RESOURCES;
                }
            } else {
                if(param->write.offset > PREPARE_BUF_MAX_SIZE) {
                    status = ESP_GATT_INVALID_OFFSET;
                } else if ((param->write.offset + param->write.len) > PREPARE_BUF_MAX_SIZE) {
                    status = ESP_GATT_INVALID_ATTR_LEN;
                }
            }
            esp_gatt_rsp_t *gatt_rsp = (esp_gatt_rsp_t *)malloc(sizeof(esp_gatt_rsp_t));
            gatt_rsp->attr_value.len = param->write.len;
            gatt_rsp->attr_value.handle = param->write.handle;
            gatt_rsp->attr_value.offset = param->write.offset;
            gatt_rsp->attr_value.auth_req = ESP_GATT_AUTH_REQ_NONE;
            memcpy(gatt_rsp->attr_value.value, param->write.value, param->write.len);
            esp_err_t response_err = esp_ble_gatts_send_response(gatts_if, param->write.conn_id, param->write.trans_id, status, gatt_rsp);
            if (response_err != ESP_OK){
               ESP_LOGE(GATTS_TAG, "Send response error\n");
            }
            free(gatt_rsp);
            if (status != ESP_GATT_OK){
                return;
            }
            memcpy(prepare_write_env->prepare_buf + param->write.offset,
                   param->write.value,
                   param->write.len);
            prepare_write_env->prepare_len += param->write.len;
        }else{
            esp_ble_gatts_send_response(gatts_if, param->write.conn_id, param->write.trans_id, status, NULL);
        }
    }
}
void example_exec_write_event_env(prepare_type_env_t *prepare_write_env, esp_ble_gatts_cb_param_t *param){
    printf("example_exec_write_event_env\n");
    if (param->exec_write.exec_write_flag == ESP_GATT_PREP_WRITE_EXEC){
        esp_log_buffer_hex(GATTS_TAG, prepare_write_env->prepare_buf, prepare_write_env->prepare_len);
    }else{
        ESP_LOGI(GATTS_TAG,"ESP_GATT_PREP_WRITE_CANCEL");
    }
    if (prepare_write_env->prepare_buf) {
        free(prepare_write_env->prepare_buf);
        prepare_write_env->prepare_buf = NULL;
    }
    prepare_write_env->prepare_len = 0;
}
static void gatts_profile_a_event_handler(esp_gatts_cb_event_t event, esp_gatt_if_t gatts_if, esp_ble_gatts_cb_param_t *param) {
    switch (event) {
    case ESP_GATTS_REG_EVT:
        printf("ESP_GATTS_REG_EVT\n");
        ESP_LOGI(GATTS_TAG, "REGISTER_APP_EVT, status %d, app_id %d\n", param->reg.status, param->reg.app_id);
        gl_profile_tab[PROFILE_A_APP_ID].service_id.is_primary = true;
        gl_profile_tab[PROFILE_A_APP_ID].service_id.id.inst_id = 0x00;
        gl_profile_tab[PROFILE_A_APP_ID].service_id.id.uuid.len = ESP_UUID_LEN_16;
        gl_profile_tab[PROFILE_A_APP_ID].service_id.id.uuid.uuid.uuid16 = GATTS_SERVICE_UUID;
        esp_err_t set_dev_name_ret = esp_ble_gap_set_device_name(TEST_DEVICE_NAME);
        if (set_dev_name_ret){
            ESP_LOGE(GATTS_TAG, "set device name failed, error code = %x", set_dev_name_ret);
        }
#ifdef CONFIG_SET_RAW_ADV_DATA
        esp_err_t raw_adv_ret = esp_ble_gap_config_adv_data_raw(raw_adv_data, sizeof(raw_adv_data));
        if (raw_adv_ret){
            ESP_LOGE(GATTS_TAG, "config raw adv data failed, error code = %x ", raw_adv_ret);
        }
        adv_config_done |= adv_config_flag;
        esp_err_t raw_scan_ret = esp_ble_gap_config_scan_rsp_data_raw(raw_scan_rsp_data, sizeof(raw_scan_rsp_data));
        if (raw_scan_ret){
            ESP_LOGE(GATTS_TAG, "config raw scan rsp data failed, error code = %x", raw_scan_ret);
        }
        adv_config_done |= scan_rsp_config_flag;
#else
        //config adv data
        esp_err_t ret = esp_ble_gap_config_adv_data(&adv_data);
        if (ret){
            ESP_LOGE(GATTS_TAG, "config adv data failed, error code = %x", ret);
        }
        adv_config_done |= adv_config_flag;
        //config scan response data
        ret = esp_ble_gap_config_adv_data(&scan_rsp_data);
        if (ret){
            ESP_LOGE(GATTS_TAG, "config scan response data failed, error code = %x", ret);
        }
        adv_config_done |= scan_rsp_config_flag;
#endif
        esp_ble_gatts_create_service(gatts_if, &gl_profile_tab[PROFILE_A_APP_ID].service_id, GATTS_NUM_HANDLE_TEST_A);
        break;
    case ESP_GATTS_READ_EVT: {
        printf("ESP_GATTS_READ_EVT\n");
        ESP_LOGI(GATTS_TAG, "GATT_READ_EVT, conn_id %d, trans_id %d, handle %d\n", param->read.conn_id, param->read.trans_id, param->read.handle);
        esp_gatt_rsp_t rsp;
        memset(&rsp, 0, sizeof(esp_gatt_rsp_t));
        rsp.attr_value.handle = param->read.handle;
        rsp.attr_value.len = 4;
        rsp.attr_value.value[0] = 0xde;
        rsp.attr_value.value[1] = 0xed;
        rsp.attr_value.value[2] = 0xbe;
        rsp.attr_value.value[3] = 0xef;
        esp_ble_gatts_send_response(gatts_if, param->read.conn_id, param->read.trans_id,
                                    ESP_GATT_OK, &rsp);
        break;
    }

    case ESP_GATTS_WRITE_EVT: {
        ESP_LOGI(GATTS_TAG, "GATT_WRITE_EVT, conn_id %d, trans_id %d, handle %d", param->write.conn_id, param->write.trans_id, param->write.handle);
        if (!param->write.is_prep){
            ESP_LOGI(GATTS_TAG, "GATT_WRITE_EVT, value len %d, value :", param->write.len);
            esp_log_buffer_hex(GATTS_TAG, param->write.value, param->write.len);
            printf("param->write.len = %u \n",param->write.len);
            for (int i =0; i<=param->write.len;i++){
                printf("data received = %u \n",param->write.value[i]);
            }
            if (gl_profile_tab[PROFILE_A_APP_ID].descr_handle == param->write.handle && param->write.len == 2){
                uint16_t descr_value = param->write.value[1]<<8 | param->write.value[0];
                if (descr_value == 0x0001){
                    if (a_property & ESP_GATT_CHAR_PROP_BIT_NOTIFY){
                        ESP_LOGI(GATTS_TAG, "notify enable");
                        uint8_t notify_data[15];
                        for (int i = 0; i < sizeof(notify_data); ++i)
                        {
                            notify_data[i] = i%0xff;
                        }
                        //the size of notify_data[] need less than MTU size
                        esp_ble_gatts_send_indicate(gatts_if, param->write.conn_id, gl_profile_tab[PROFILE_A_APP_ID].char_handle,
                                                sizeof(notify_data), notify_data, false);
                    }
                }else if (descr_value == 0x0002){
                    if (a_property & ESP_GATT_CHAR_PROP_BIT_INDICATE){
                        ESP_LOGI(GATTS_TAG, "indicate enable");
                        uint8_t indicate_data[15];
                        for (int i = 0; i < sizeof(indicate_data); ++i)
                        {
                            indicate_data[i] = i%0xff;
                        }
                        //the size of indicate_data[] need less than MTU size
                        esp_ble_gatts_send_indicate(gatts_if, param->write.conn_id, gl_profile_tab[PROFILE_A_APP_ID].char_handle,
                                                sizeof(indicate_data), indicate_data, true);
                    }
                }
                else if (descr_value == 0x0000){
                    ESP_LOGI(GATTS_TAG, "notify/indicate disable ");
                }else{
                    ESP_LOGE(GATTS_TAG, "unknown descr value");
                    esp_log_buffer_hex(GATTS_TAG, param->write.value, param->write.len);
                }
            }
        }
        example_write_event_env(gatts_if, &a_prepare_write_env, param);
        break;
    }
    case ESP_GATTS_EXEC_WRITE_EVT:
        ESP_LOGI(GATTS_TAG,"ESP_GATTS_EXEC_WRITE_EVT");
        esp_ble_gatts_send_response(gatts_if, param->write.conn_id, param->write.trans_id, ESP_GATT_OK, NULL);
        example_exec_write_event_env(&a_prepare_write_env, param);
        break;
    case ESP_GATTS_MTU_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_MTU_EVT, MTU %d", param->mtu.mtu);
        break;
    case ESP_GATTS_UNREG_EVT:
        break;
    case ESP_GATTS_CREATE_EVT:
        printf("ESP_GATTS_CREATE_EVT\n");
        //adding first charasteristic
        ESP_LOGI(GATTS_TAG, "CREATE_SERVICE_EVT, status %d,  service_handle %d\n", param->create.status, param->create.service_handle);
        gl_profile_tab[PROFILE_A_APP_ID].service_handle = param->create.service_handle;
        gl_profile_tab[PROFILE_A_APP_ID].char_uuid.len = ESP_UUID_LEN_16;
        gl_profile_tab[PROFILE_A_APP_ID].char_uuid.uuid.uuid16 = GATTS_CHAR1_UUID;
        printf("esp_ble_gatts_start_service \n");
        esp_ble_gatts_start_service(gl_profile_tab[PROFILE_A_APP_ID].service_handle);
        a_property = ESP_GATT_CHAR_PROP_BIT_READ | ESP_GATT_CHAR_PROP_BIT_NOTIFY | ESP_GATT_CHAR_PROP_BIT_WRITE;
        esp_err_t add_char_ret = esp_ble_gatts_add_char(gl_profile_tab[PROFILE_A_APP_ID].service_handle, &gl_profile_tab[PROFILE_A_APP_ID].char_uuid,
                                                        ESP_GATT_PERM_READ | ESP_GATT_PERM_WRITE,
                                                        a_property,
                                                        &gatts_demo_char1_val, NULL);
        if (add_char_ret){
            ESP_LOGE(GATTS_TAG, "add char failed, error code =%x",add_char_ret);
        }

        //adding second charasteristic
/*
        gl_profile_tab[PROFILE_A_APP_ID].char_uuid.len = ESP_UUID_LEN_16;
        gl_profile_tab[PROFILE_A_APP_ID].char_uuid.uuid.uuid16 = GATTS_CHAR2_UUID;
        a2_property =  ESP_GATT_CHAR_PROP_BIT_WRITE ;
        add_char_ret = esp_ble_gatts_add_char(gl_profile_tab[PROFILE_A_APP_ID].service_handle, &gl_profile_tab[PROFILE_A_APP_ID].char_uuid,
                                                        ESP_GATT_PERM_READ | ESP_GATT_PERM_WRITE,
                                                        a2_property,
                                                        &gatts_demo_char1_val, NULL);
        if (add_char_ret){
            ESP_LOGE(GATTS_TAG, "add char failed, error code =%x",add_char_ret);
        }
*/

        break;
    case ESP_GATTS_ADD_INCL_SRVC_EVT:
        break;
    case ESP_GATTS_ADD_CHAR_EVT: {
        printf("ESP_GATTS_ADD_CHAR_EVT\n");
        uint16_t length = 0;
        //const uint8_t *prf_char;
        ESP_LOGI(GATTS_TAG, "ADD_CHAR_EVT, status %d,  attr_handle %d, service_handle %d\n",
                param->add_char.status, param->add_char.attr_handle, param->add_char.service_handle);
        gl_profile_tab[PROFILE_A_APP_ID].char_handle = param->add_char.attr_handle;
        gl_profile_tab[PROFILE_A_APP_ID].descr_uuid.len = ESP_UUID_LEN_16;
        gl_profile_tab[PROFILE_A_APP_ID].descr_uuid.uuid.uuid16 = ESP_GATT_UUID_CHAR_CLIENT_CONFIG;
        /*
        esp_err_t get_attr_ret = esp_ble_gatts_get_attr_value(param->add_char.attr_handle,  &length, &prf_char);
        if (get_attr_ret == ESP_FAIL){
            ESP_LOGE(GATTS_TAG, "ILLEGAL HANDLE");
        }
        ESP_LOGI(GATTS_TAG, "the gatts demo char length = %x\n", length);
        for(int i = 0; i < length; i++){
            ESP_LOGI(GATTS_TAG, "prf_char[%x] =%x\n",i,prf_char[i]);
        }
        */
        esp_err_t add_descr_ret = esp_ble_gatts_add_char_descr(gl_profile_tab[PROFILE_A_APP_ID].service_handle, &gl_profile_tab[PROFILE_A_APP_ID].descr_uuid,
                                                                ESP_GATT_PERM_READ | ESP_GATT_PERM_WRITE, NULL, NULL);
        if (add_descr_ret){
            ESP_LOGE(GATTS_TAG, "add char descr failed, error code =%x", add_descr_ret);
        }
        break;
    }
    case ESP_GATTS_ADD_CHAR_DESCR_EVT:
    printf("ESP_GATTS_ADD_CHAR_DESCR_EVT\n");
        gl_profile_tab[PROFILE_A_APP_ID].descr_handle = param->add_char_descr.attr_handle;
        ESP_LOGI(GATTS_TAG, "ADD_DESCR_EVT, status %d, attr_handle %d, service_handle %d\n",
                 param->add_char_descr.status, param->add_char_descr.attr_handle, param->add_char_descr.service_handle);
        break;
    case ESP_GATTS_DELETE_EVT:
        break;
    case ESP_GATTS_START_EVT:
        printf("ESP_GATTS_START_EVT\n");
        ESP_LOGI(GATTS_TAG, "SERVICE_START_EVT, status %d, service_handle %d\n",
                 param->start.status, param->start.service_handle);
        break;
    case ESP_GATTS_STOP_EVT:
        break;
    case ESP_GATTS_CONNECT_EVT: {
        printf("ESP_GATTS_CONNECT_EVT\n");
        esp_ble_conn_update_params_t conn_params = {0};
        memcpy(conn_params.bda, param->connect.remote_bda, sizeof(esp_bd_addr_t));
        /* For the IOS system, please reference the apple official documents about the ble connection parameters restrictions. */
        conn_params.latency = 0;
        conn_params.max_int = 0x20;    // max_int = 0x20*1.25ms = 40ms
        conn_params.min_int = 0x10;    // min_int = 0x10*1.25ms = 20ms
        conn_params.timeout = 400;    // timeout = 400*10ms = 4000ms
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_CONNECT_EVT, conn_id %d, remote %02x:%02x:%02x:%02x:%02x:%02x:",
                 param->connect.conn_id,
                 param->connect.remote_bda[0], param->connect.remote_bda[1], param->connect.remote_bda[2],
                 param->connect.remote_bda[3], param->connect.remote_bda[4], param->connect.remote_bda[5]);
        gl_profile_tab[PROFILE_A_APP_ID].conn_id = param->connect.conn_id;
        //start sent the update connection parameters to the peer device.
        esp_ble_gap_update_conn_params(&conn_params);
        break;
    }
    case ESP_GATTS_DISCONNECT_EVT:
        printf("ESP_GATTS_DISCONNECT_EVT\n");
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_DISCONNECT_EVT, disconnect reason 0x%x", param->disconnect.reason);
        esp_ble_gap_start_advertising(&adv_params);
        break;
    case ESP_GATTS_CONF_EVT:
        printf("ESP_GATTS_CONF_EVT\n");
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_CONF_EVT, status %d attr_handle %d", param->conf.status, param->conf.handle);
        if (param->conf.status != ESP_GATT_OK){
            esp_log_buffer_hex(GATTS_TAG, param->conf.value, param->conf.len);
        }
        break;
    case ESP_GATTS_OPEN_EVT:
    case ESP_GATTS_CANCEL_OPEN_EVT:
    case ESP_GATTS_CLOSE_EVT:
    case ESP_GATTS_LISTEN_EVT:
    case ESP_GATTS_CONGEST_EVT:
    default:
        break;
    }
}


static void gatts_event_handler(esp_gatts_cb_event_t event, esp_gatt_if_t gatts_if, esp_ble_gatts_cb_param_t *param)
{
    /* If event is register event, store the gatts_if for each profile */
    if (event == ESP_GATTS_REG_EVT) {
        if (param->reg.status == ESP_GATT_OK) {
            gl_profile_tab[param->reg.app_id].gatts_if = gatts_if;
        } else {
            ESP_LOGI(GATTS_TAG, "Reg app failed, app_id %04x, status %d\n",
                    param->reg.app_id,
                    param->reg.status);
            return;
        }
    }
    /* If the gatts_if equal to profile A, call profile A cb handler,
     * so here call each profile's callback */
    do {
        int idx;
        for (idx = 0; idx < PROFILE_NUM; idx++) {
            if (gatts_if == ESP_GATT_IF_NONE || /* ESP_GATT_IF_NONE, not specify a certain gatt_if, need to call every profile cb function */
                    gatts_if == gl_profile_tab[idx].gatts_if) {
                if (gl_profile_tab[idx].gatts_cb) {
                    gl_profile_tab[idx].gatts_cb(event, gatts_if, param);
                }
            }
        }
    } while (0);
}
void BLE_setup()
{
    esp_err_t ret;

    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
    esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
    ret = esp_bt_controller_init(&bt_cfg);
    if (ret) {
        ESP_LOGE(GATTS_TAG, "%s initialize controller failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }

    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
    if (ret) {
        ESP_LOGE(GATTS_TAG, "%s enable controller failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }
    ret = esp_bluedroid_init();
    if (ret) {
        ESP_LOGE(GATTS_TAG, "%s init bluetooth failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }
    ret = esp_bluedroid_enable();
    if (ret) {
        ESP_LOGE(GATTS_TAG, "%s enable bluetooth failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }
    ret = esp_ble_gatts_register_callback(gatts_event_handler);
    if (ret){
        ESP_LOGE(GATTS_TAG, "gatts register error, error code = %x", ret);
        return;
    }
    ret = esp_ble_gap_register_callback(gap_event_handler);
    if (ret){
        ESP_LOGE(GATTS_TAG, "gap register error, error code = %x", ret);
        return;
    }
    ret = esp_ble_gatts_app_register(PROFILE_A_APP_ID);
    if (ret){
        ESP_LOGE(GATTS_TAG, "gatts app register error, error code = %x", ret);
        return;
    }
    esp_err_t local_mtu_ret = esp_ble_gatt_set_local_mtu(500);
    if (local_mtu_ret){
        ESP_LOGE(GATTS_TAG, "set local  MTU failed, error code = %x", local_mtu_ret);
    }
    return;
}
I hope someone here have a lot of experience with esp-idf. I have tried looking how other people have done but this seems like a very common issue and no clear solution
 
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