本人想用esp32读取串口数据并且通过MQTT协议传到公共服务器端，但出现了下面的问题：

（1）如果将串口设置波特率为115200，则能够立马连上wifi和服务器，但是读取不了串口数据发不上服务器端。

因为所连接开发板传输数据的波特率为4800，所以将波特率改为4800时，wifi和mqtt都连接不成功，出现了以下情况：

代码如下：

#include #include #include #include #include "esp_wifi.h"#include "esp_system.h"#include "nvs_flash.h"#include "esp_event.h"#include "esp_netif.h"#include "protocol_examples_common.h"

#include "freertos/FreeRTOS.h"#include "freertos/task.h"#include "freertos/semphr.h"#include "freertos/queue.h"

#include "lwip/sockets.h"#include "lwip/dns.h"#include "lwip/netdb.h"

#include "esp_log.h"#include "mqtt_client.h"

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

#include "driver/uart.h"

static const char *TAG = "MQTT_EXAMPLE";

#define EX_UART_NUM UART_NUM_0#define PATTERN_CHR_NUM (3) /*!< Set the number of consecutive and identical characters received by receiver which defines a UART pattern*/

#define BUF_SIZE (1024)#define RD_BUF_SIZE (BUF_SIZE)static QueueHandle_t uart0_queue;

esp_mqtt_event_handle_t event;esp_mqtt_client_handle_t client;

static void uart_event_task(void *pvParameters){ uart_event_t event; size_t buffered_size; uint8_t* dtmp = (uint8_t*) malloc(RD_BUF_SIZE); for(;;) { //Waiting for UART event. if(xQueueReceive(uart0_queue, (void * )&event, (TickType_t)portMAX_DELAY)) { bzero(dtmp, RD_BUF_SIZE); const char *abv = (const char*)dtmp;

switch(event.type) { //Event of UART receving data /*We'd better handler data event fast, there would be much more data events than other types of events. If we take too much time on data event, the queue might be full.*/ case UART_DATA: uart_read_bytes(EX_UART_NUM, dtmp, event.size, portMAX_DELAY);

esp_mqtt_client_publish(client, "/test/shixi", event.size, 0, 1, 0);

break; //Event of HW FIFO overflow detected case UART_FIFO_OVF: ESP_LOGI(TAG, "hw fifo overflow"); // If fifo overflow happened, you should consider adding flow control for your application. // The ISR has already reset the rx FIFO, // As an example, we directly flush the rx buffer here in order to read more data. uart_flush_input(EX_UART_NUM); xQueueReset(uart0_queue); break; //Event of UART ring buffer full case UART_BUFFER_FULL: ESP_LOGI(TAG, "ring buffer full"); // If buffer full happened, you should consider encreasing your buffer size // As an example, we directly flush the rx buffer here in order to read more data. uart_flush_input(EX_UART_NUM); xQueueReset(uart0_queue); break; //Event of UART RX break detected case UART_BREAK: ESP_LOGI(TAG, "uart rx break"); break; //Event of UART parity check error case UART_PARITY_ERR: ESP_LOGI(TAG, "uart parity error"); break; //Event of UART frame error case UART_FRAME_ERR: ESP_LOGI(TAG, "uart frame error"); break; //Others default: ESP_LOGI(TAG, "uart event type: %d", event.type); break; } } } free(dtmp); dtmp = NULL; vTaskDelete(NULL);}

void UART_Init(void){ /* Configure parameters of an UART driver, * communication pins and install the driver */ uart_config_t uart_config = { .baud_rate = 4800, .data_bits = UART_DATA_8_BITS, .parity = UART_PARITY_DISABLE, .stop_bits = UART_STOP_BITS_1, .flow_ctrl = UART_HW_FLOWCTRL_DISABLE, .source_clk = UART_SCLK_DEFAULT, }; //Install UART driver, and get the queue. uart_driver_install(EX_UART_NUM, BUF_SIZE * 2, BUF_SIZE * 2, 20, &uart0_queue, 0); uart_param_config(EX_UART_NUM, &uart_config);

//Set UART log level esp_log_level_set(TAG, ESP_LOG_INFO); //Set UART pins (using UART0 default pins ie no changes.) uart_set_pin(EX_UART_NUM, 17, 16, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);

//Create a task to handler UART event from ISR xTaskCreate(uart_event_task, "uart_event_task", 2048, NULL, 12, NULL);

}

static void log_error_if_nonzero(const char *message, int error_code){ if (error_code != 0) { ESP_LOGE(TAG, "Last error %s: 0x%x", message, error_code); }}

/* * @brief Event handler registered to receive MQTT events * * This function is called by the MQTT client event loop. * * @param handler_args user data registered to the event. * @param base Event base for the handler(always MQTT Base in this example). * @param event_id The id for the received event. * @param event_data The data for the event, esp_mqtt_event_handle_t. */

static void mqtt_event_handler(void *handler_args, esp_event_base_t base, int32_t event_id, void *event_data){ ESP_LOGD(TAG, "Event dispatched from event loop base=%s, event_id=%d", base, event_id); event = event_data; client = event->client; int msg_id; switch ((esp_mqtt_event_id_t)event_id) { case MQTT_EVENT_CONNECTED: ESP_LOGI(TAG, "MQTT_EVENT_CONNECTED"); msg_id = esp_mqtt_client_publish(client, "/topic/qos1", "data_3", 0, 1, 0); ESP_LOGI(TAG, "sent publish successful, msg_id=%d", msg_id);

msg_id = esp_mqtt_client_subscribe(client, "/topic/qos0", 0); ESP_LOGI(TAG, "sent subscribe successful, msg_id=%d", msg_id);

msg_id = esp_mqtt_client_subscribe(client, "/topic/qos1", 1); ESP_LOGI(TAG, "sent subscribe successful, msg_id=%d", msg_id);

msg_id = esp_mqtt_client_unsubscribe(client, "/topic/qos1"); ESP_LOGI(TAG, "sent unsubscribe successful, msg_id=%d", msg_id); break; case MQTT_EVENT_DISCONNECTED: ESP_LOGI(TAG, "MQTT_EVENT_DISCONNECTED"); break;

case MQTT_EVENT_SUBSCRIBED: ESP_LOGI(TAG, "MQTT_EVENT_SUBSCRIBED, msg_id=%d", event->msg_id); msg_id = esp_mqtt_client_publish(client, "/topic/qos0", "data", 0, 0, 0); ESP_LOGI(TAG, "sent publish successful, msg_id=%d", msg_id); break; case MQTT_EVENT_UNSUBSCRIBED: ESP_LOGI(TAG, "MQTT_EVENT_UNSUBSCRIBED, msg_id=%d", event->msg_id); break; case MQTT_EVENT_PUBLISHED: ESP_LOGI(TAG, "MQTT_EVENT_PUBLISHED, msg_id=%d", event->msg_id); break; case MQTT_EVENT_DATA: ESP_LOGI(TAG, "MQTT_EVENT_DATA"); printf("TOPIC=%.*s\r\n", event->topic_len, event->topic); printf("DATA=%.*s\r\n", event->data_len, event->data); break; case MQTT_EVENT_ERROR: ESP_LOGI(TAG, "MQTT_EVENT_ERROR"); if (event->error_handle->error_type == MQTT_ERROR_TYPE_TCP_TRANSPORT) { log_error_if_nonzero("reported from esp-tls", event->error_handle->esp_tls_last_esp_err); log_error_if_nonzero("reported from tls stack", event->error_handle->esp_tls_stack_err); log_error_if_nonzero("captured as transport's socket errno", event->error_handle->esp_transport_sock_errno); ESP_LOGI(TAG, "Last errno string (%s)", strerror(event->error_handle->esp_transport_sock_errno));

} break; default: ESP_LOGI(TAG, "Other event id:%d", event->event_id); break; }}

static void mqtt_app_start(void){ esp_mqtt_client_config_t mqtt_cfg = { .broker.address.uri = "mqtt://http://broker.emqx.io", .broker.address.port = 1883, };#if CONFIG_BROKER_URL_FROM_STDIN char line[128];

if (strcmp(mqtt_cfg.broker.address.uri, "FROM_STDIN") == 0) { int count = 0; printf("Please enter url of mqtt broker\n"); while (count < 128) { int c = fgetc(stdin); if (c == '\n') { line[count] = '\0'; break; } else if (c > 0 && c < 127) { line[count] = c; ++count; } vTaskDelay(10 / portTICK_PERIOD_MS); } mqtt_cfg.broker.address.uri = line; printf("Broker url: %s\n", line); } else { ESP_LOGE(TAG, "Configuration mismatch: wrong broker url"); abort(); }#endif /* CONFIG_BROKER_URL_FROM_STDIN */

esp_mqtt_client_handle_t client = esp_mqtt_client_init(&mqtt_cfg); /* The last argument may be used to pass data to the event handler, in this example mqtt_event_handler */ esp_mqtt_client_register_event(client, ESP_EVENT_ANY_ID, mqtt_event_handler, NULL); esp_mqtt_client_start(client);}

void app_main(void){ ESP_LOGI(TAG, "[APP] Startup.."); ESP_LOGI(TAG, "[APP] Free memory: %d bytes", esp_get_free_heap_size()); ESP_LOGI(TAG, "[APP] IDF version: %s", esp_get_idf_version());

esp_log_level_set("*", ESP_LOG_INFO); esp_log_level_set("mqtt_client", ESP_LOG_VERBOSE); esp_log_level_set("MQTT_EXAMPLE", ESP_LOG_VERBOSE); esp_log_level_set("TRANSPORT_BASE", ESP_LOG_VERBOSE); esp_log_level_set("esp-tls", ESP_LOG_VERBOSE); esp_log_level_set("TRANSPORT", ESP_LOG_VERBOSE); esp_log_level_set("outbox", ESP_LOG_VERBOSE);

ESP_ERROR_CHECK(nvs_flash_init()); ESP_ERROR_CHECK(esp_netif_init()); ESP_ERROR_CHECK(esp_event_loop_create_default());

/* This helper function configures Wi-Fi or Ethernet, as selected in menuconfig. * Read "Establishing Wi-Fi or Ethernet Connection" section in * examples/protocols/README.md for more information about this function. */ ESP_ERROR_CHECK(example_connect());

mqtt_app_start();

UART_Init();}

求求大佬帮忙 能不能帮忙看一下哪出了问题，怎么处理？？？？？？？