ESP32 BT write echo back once

[joe@shkila.com]

Hi,
I'm new to esp32, and i want to use the bluetooth feature
I've taken the spp_accepter example and add it the spp_initiator example
here's the outcome:

Code: Select all

/*
   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.
*/

#include <stdint.h>
#include <string.h>
#include <stdbool.h>
#include <stdio.h>
#include "nvs.h"
#include "nvs_flash.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_bt.h"
#include "esp_bt_main.h"
#include "esp_gap_bt_api.h"
#include "esp_bt_device.h"
#include "esp_spp_api.h"

#include "time.h"
#include "sys/time.h"

#define SPP_TAG "SPP_ACCEPTOR_DEMO"
#define SPP_SERVER_NAME "SPP_SERVER"
#define EXCAMPLE_DEVICE_NAME "ESP_SPP_ACCEPTOR"
#define SPP_SHOW_DATA 0
#define SPP_SHOW_SPEED 1
#define SPP_SHOW_MODE SPP_SHOW_DATA    /*Choose show mode: show data or speed*/

static const esp_spp_mode_t esp_spp_mode = ESP_SPP_MODE_CB;

static struct timeval time_new, time_old;
static long data_num = 0;

static const esp_spp_sec_t sec_mask = ESP_SPP_SEC_AUTHENTICATE;
static const esp_spp_role_t role_slave = ESP_SPP_ROLE_SLAVE;


#if (SPP_SHOW_MODE == SPP_SHOW_DATA)
#define SPP_DATA_LEN 20
#else
#define SPP_DATA_LEN ESP_SPP_MAX_MTU
#endif
static uint8_t spp_data[SPP_DATA_LEN];
static int send = 0;

static void print_speed(void)
{
    float time_old_s = time_old.tv_sec + time_old.tv_usec / 1000000.0;
    float time_new_s = time_new.tv_sec + time_new.tv_usec / 1000000.0;
    float time_interval = time_new_s - time_old_s;
    float speed = data_num * 8 / time_interval / 1000.0;
    ESP_LOGI(SPP_TAG, "speed(%fs ~ %fs): %f kbit/s" , time_old_s, time_new_s, speed);
    data_num = 0;
    time_old.tv_sec = time_new.tv_sec;
    time_old.tv_usec = time_new.tv_usec;
}

static void esp_spp_cb(esp_spp_cb_event_t event, esp_spp_cb_param_t *param)
{
    switch (event) {
    case ESP_SPP_INIT_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_INIT_EVT");
        esp_bt_dev_set_device_name(EXCAMPLE_DEVICE_NAME);
        esp_bt_gap_set_scan_mode(ESP_BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE);
        esp_spp_start_srv(sec_mask,role_slave, 0, SPP_SERVER_NAME);
        break;
    case ESP_SPP_DISCOVERY_COMP_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_DISCOVERY_COMP_EVT");
        break;
    case ESP_SPP_OPEN_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_OPEN_EVT");
        break;
    case ESP_SPP_CLOSE_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_CLOSE_EVT");
        break;
    case ESP_SPP_START_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_START_EVT");
        break;
    case ESP_SPP_CL_INIT_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_CL_INIT_EVT");
        break;
    case ESP_SPP_DATA_IND_EVT:
#if (SPP_SHOW_MODE == SPP_SHOW_DATA)
        ESP_LOGI(SPP_TAG, "ESP_SPP_DATA_IND_EVT len=%d handle=%d",
                 param->data_ind.len, param->data_ind.handle);
        esp_log_buffer_hex("",param->data_ind.data,param->data_ind.len);
		
		for (int i = 0; i < param->data_ind.len; ++i) {
			spp_data[i] = param->data_ind.data[i];
		}
		 esp_spp_write(param->data_ind.handle, param->data_ind.len, param->data_ind.data);
#else
        gettimeofday(&time_new, NULL);
        data_num += param->data_ind.len;
        if (time_new.tv_sec - time_old.tv_sec >= 3) {
            print_speed();
        }
#endif
        break;
    case ESP_SPP_CONG_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_CONG_EVT");
		#if (SPP_SHOW_MODE == SPP_SHOW_DATA)
        ESP_LOGI(SPP_TAG, "ESP_SPP_CONG_EVT cong=%d", param->cong.cong);
#endif
        if (param->cong.cong == 0) {
            esp_spp_write(param->cong.handle, SPP_DATA_LEN, spp_data);
        }
        break;
    case ESP_SPP_WRITE_EVT:
       #if (SPP_SHOW_MODE == SPP_SHOW_DATA)
        ESP_LOGI(SPP_TAG, "ESP_SPP_WRITE_EVT len=%d cong=%d", param->write.len , param->write.cong);
        esp_log_buffer_hex("",spp_data,param->write.len);
		
#else
        gettimeofday(&time_new, NULL);
        data_num += param->write.len;
        if (time_new.tv_sec - time_old.tv_sec >= 3) {
            print_speed();
        }
#endif
        if (param->write.cong == 0) {
			ESP_LOGI(SPP_TAG, "Yeah len=%d cong=%d", param->write.len , param->write.cong);
            esp_spp_write(param->write.handle, param->write.len, spp_data);			
        }
        break;
    case ESP_SPP_SRV_OPEN_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_SRV_OPEN_EVT");
        gettimeofday(&time_old, NULL);
        break;
    default:
        break;
    }
}

void esp_bt_gap_cb(esp_bt_gap_cb_event_t event, esp_bt_gap_cb_param_t *param)
{
    switch (event) {
    case ESP_BT_GAP_AUTH_CMPL_EVT:{
        if (param->auth_cmpl.stat == ESP_BT_STATUS_SUCCESS) {
            ESP_LOGI(SPP_TAG, "authentication success: %s", param->auth_cmpl.device_name);
            esp_log_buffer_hex(SPP_TAG, param->auth_cmpl.bda, ESP_BD_ADDR_LEN);
        } else {
            ESP_LOGE(SPP_TAG, "authentication failed, status:%d", param->auth_cmpl.stat);
        }
        break;
    }
    case ESP_BT_GAP_PIN_REQ_EVT:{
        ESP_LOGI(SPP_TAG, "ESP_BT_GAP_PIN_REQ_EVT min_16_digit:%d", param->pin_req.min_16_digit);
        if (param->pin_req.min_16_digit) {
            ESP_LOGI(SPP_TAG, "Input pin code: 0000 0000 0000 0000");
            esp_bt_pin_code_t pin_code = {0};
            esp_bt_gap_pin_reply(param->pin_req.bda, true, 16, pin_code);
        } else {
            ESP_LOGI(SPP_TAG, "Input pin code: 1234");
            esp_bt_pin_code_t pin_code;
            pin_code[0] = '1';
            pin_code[1] = '2';
            pin_code[2] = '3';
            pin_code[3] = '4';
            esp_bt_gap_pin_reply(param->pin_req.bda, true, 4, pin_code);
        }
        break;
    }
    case ESP_BT_GAP_CFM_REQ_EVT:
        ESP_LOGI(SPP_TAG, "ESP_BT_GAP_CFM_REQ_EVT Please compare the numeric value: %d", param->cfm_req.num_val);
        esp_bt_gap_ssp_confirm_reply(param->cfm_req.bda, true);
        break;
    case ESP_BT_GAP_KEY_NOTIF_EVT:
        ESP_LOGI(SPP_TAG, "ESP_BT_GAP_KEY_NOTIF_EVT passkey:%d", param->key_notif.passkey);
        break;
    case ESP_BT_GAP_KEY_REQ_EVT:
        ESP_LOGI(SPP_TAG, "ESP_BT_GAP_KEY_REQ_EVT Please enter passkey!");
        break;
    default: {
        ESP_LOGI(SPP_TAG, "event: %d", event);
        break;
    }
    }
    return;
}

void app_main()
{
	for (int i = 0; i < SPP_DATA_LEN; ++i) {
        spp_data[i] = i;
    }
	
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
    }
    ESP_ERROR_CHECK( ret );

    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(SPP_TAG, "%s initialize controller failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }

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

    if ((ret = esp_bluedroid_init()) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s initialize bluedroid failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }

    if ((ret = esp_bluedroid_enable()) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s enable bluedroid failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }

    if ((ret = esp_bt_gap_register_callback(esp_bt_gap_cb)) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s gap register failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }

    if ((ret = esp_spp_register_callback(esp_spp_cb)) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s spp register failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }

    if ((ret = esp_spp_init(esp_spp_mode)) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s spp init failed: %s\n", __func__, esp_err_to_name(ret));
        return;
    }

    /* Set default parameters for Secure Simple Pairing */
    esp_bt_sp_param_t param_type = ESP_BT_SP_IOCAP_MODE;
    esp_bt_io_cap_t iocap = ESP_BT_IO_CAP_IO;
    esp_bt_gap_set_security_param(param_type, &iocap, sizeof(uint8_t));

    /*
     * Set default parameters for Legacy Pairing
     * Use variable pin, input pin code when pairing
     */
    esp_bt_pin_type_t pin_type = ESP_BT_PIN_TYPE_VARIABLE;
    esp_bt_pin_code_t pin_code;
    esp_bt_gap_set_pin(pin_type, 0, pin_code);
}

as you can see i'm trying to do echo. meanning getting data from another bluetooth device (my phone) and send it back
i'm recieving the data and when i send it back, i'm getting the data all the time until cong = 1 and then the connection is lost
how can i send only once the response, meanning, if i send from my phone "hello world" how can i make ESP32 send it back just once?

[ESP_Sprite]

Moved to the ESP32 IDF forum.

[gunar.kroeger]

When you recieve a message, you get an ESP_SPP_DATA_IND_EVT event, when you finish transmiting a message, you get an ESP_SPP_WRITE_EVT.
What you are doing now is sending an echo once you recieve AND each time you finish a transmission.

removing these lines from the ESP_SPP_WRITE_EVT case should do the trick:

Code: Select all

        if (param->write.cong == 0) {
			ESP_LOGI(SPP_TAG, "Yeah len=%d cong=%d", param->write.len , param->write.cong);
            esp_spp_write(param->write.handle, param->write.len, spp_data);			
        }