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B站Michale_ee——ESP32_IDF SDK——FreeRTOS_8 消息缓冲区

news 来源：原创 2025/5/3 8:00:43

Message Buffer（消息缓冲区）与Stream Buffer（流数据缓冲区）类似，但有2点不同：
- Message Buffer每次只接收1次完整的Message;
- Message Buffer接收缓冲区小于1条Message大小时，会接收不到数据；

一、Message Buffer每次直接收1条完整的Message

1.API简介

（1）创建Message Buffer

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（2）从消息缓冲区中接收数据

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（3）向消息缓冲区中发送数据

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2.示例代码及运行结果

#include <stdio.h>
#include <inttypes.h>
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_chip_info.h"
#include "esp_flash.h"
#include "freertos/message_buffer.h"    // add by lxl
#include "string.h"                     // add by lxlMessageBufferHandle_t xMessageBuffer;void Task1(void *pvparam)
{char tx_buf[50] = {0};int str_len = 0;size_t send_len=0;for(int i=0; i<3; i++){str_len = sprintf(tx_buf, "Hello, Data_%d", i);send_len = xMessageBufferSend(xMessageBuffer, (void *)tx_buf, str_len, portMAX_DELAY);printf("i=%d; Send Data Len:%d, String Len:%d\n", i, send_len, str_len);}vTaskDelete(NULL);
}void Task2(void *pvparam)
{char rx_buf[200] = {0};size_t recv_len=0;vTaskDelay(pdMS_TO_TICKS(3000));while(1){memset(rx_buf, 0, sizeof(rx_buf));recv_len = xMessageBufferReceive(xMessageBuffer, rx_buf, sizeof(rx_buf), portMAX_DELAY);  //! 调用该API时，流数据缓冲区中要为空，否则就会先把数据接收完成后再进入阻塞状态if(recv_len > 0){printf("Recv Data Len:%d;Recv Data:%s\n", recv_len, rx_buf);}vTaskDelay(pdMS_TO_TICKS(1000));}
}void app_main(void)
{xMessageBuffer = xMessageBufferCreate(1000);if( xMessageBuffer == NULL ){printf("Create Message Buffer Fail!\n");}else{vTaskSuspendAll();xTaskCreatePinnedToCore(Task1, "Task1", 1024*5, NULL, 1, NULL, 1);  //! ESP32-S3为双核，CPU0主要运行WiFi和蓝牙；CPU1用于运行应用程序；xTaskCreatePinnedToCore(Task2, "Task2", 1024*5, NULL, 1, NULL, 1);xTaskResumeAll();}
}

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二、Message接收API的接收缓冲区的小于1条Message大小时，会接收不到数据

示例代码及运行结果

#include <stdio.h>
#include <inttypes.h>
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_chip_info.h"
#include "esp_flash.h"
#include "freertos/Message_buffer.h"    // add by lxl
#include "string.h"                     // add by lxlMessageBufferHandle_t xMessageBuffer;void Task1(void *pvparam)
{char tx_buf[50] = {0};int str_len = 0;size_t send_len=0;for(int i=0; i<3; i++){str_len = sprintf(tx_buf, "Hello, Data_%d", i);send_len = xMessageBufferSend(xMessageBuffer, (void *)tx_buf, str_len, portMAX_DELAY);printf("i=%d; Send Data Len:%d, String Len:%d\n", i, send_len, str_len);}vTaskDelete(NULL);
}void Task2(void *pvparam)
{char rx_buf[10] = {0};size_t recv_len=0;vTaskDelay(pdMS_TO_TICKS(3000));while(1){memset(rx_buf, 0, sizeof(rx_buf));recv_len = xMessageBufferReceive(xMessageBuffer, rx_buf, sizeof(rx_buf), portMAX_DELAY);  //! 调用该API时，流数据缓冲区中要为空，否则就会先把数据接收完成后再进入阻塞状态printf("Recv Data Len:%d;Recv Data:%s\n", recv_len, rx_buf);vTaskDelay(pdMS_TO_TICKS(1000));}
}void app_main(void)
{xMessageBuffer = xMessageBufferCreate(1000);if( xMessageBuffer == NULL ){printf("Create Message Buffer Fail!\n");}else{vTaskSuspendAll();xTaskCreatePinnedToCore(Task1, "Task1", 1024*5, NULL, 1, NULL, 1);  //! ESP32-S3为双核，CPU0主要运行WiFi和蓝牙；CPU1用于运行应用程序；xTaskCreatePinnedToCore(Task2, "Task2", 1024*5, NULL, 1, NULL, 1);xTaskResumeAll();}
}