在使用数据流的时候，发现当发送数据量已经超过触发值，接收函数还是没把数据打印出来，得是发送再发一次后才会与发送的打印数据一起打印出来，但是我用win32运行freertos跑同样的代码没有这个问题，不知道是否是printf函数的问题

/********************************** (C) COPYRIGHT *******************************

 * File Name          : main.c

 * Author             : WCH

 * Version            : V1.0.0

 * Date               : 2021/06/06

 * Description        : Main program body.

*********************************************************************************

* Copyright (c) 2021 Nanjing Qinheng Microelectronics Co., Ltd.

* Attention: This software (modified or not) and binary are used for 

* microcontroller manufactured by Nanjing Qinheng Microelectronics.

*******************************************************************************/

/*

 *@Note

 task1 and task2 alternate printing

*/

#include "debug.h"

#include "FreeRTOS.h"

#include "task.h"

#include "string.h"

#include "queue.h"

#include "timers.h"

#include "stdlib.h"

#include "string.h"

#include "semphr.h"

#include "event_groups.h"

#include "stream_buffer.h"

/* Global define */

#define TASK1_TASK_PRIO     3

#define TASK1_STK_SIZE      512

#define TASK2_TASK_PRIO     1

#define TASK2_STK_SIZE      512

#define TASK3_TASK_PRIO     1

#define TASK3_STK_SIZE      512

/* Global Variable */

TaskHandle_t Task2Handle = NULL;

TaskHandle_t Task3Handle = NULL;

StreamBufferHandle_t StreamBufferHandle = NULL;

/* SemaphoreHandle */

SemaphoreHandle_t printfSemaphoreHandle = NULL;

//#define MYPRINT(format, ...)    vTaskSuspendAll();portENTER_CRITICAL();printf(format, ##__VA_ARGS__);portEXIT_CRITICAL();xTaskResumeAll()

//#define MYPRINT(format, ...)    vTaskSuspendAll();printf(format, ##__VA_ARGS__);xTaskResumeAll()

#define MYPRINT(format, ...)    xSemaphoreTake(printfSemaphoreHandle,portMAX_DELAY);printf(format, ##__VA_ARGS__);xSemaphoreGive(printfSemaphoreHandle)

/*********************************************************************

 * @fn      GPIO_Toggle_INIT

 *

 * @brief   Initializes GPIOA.0/1

 *

 * @return  none

 */

void GPIO_Toggle_INIT(void)

{

  GPIO_InitTypeDef  GPIO_InitStructure={0};

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

  GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

}

/*********************************************************************

 * @fn      task1_task

 *

 * @brief   task1 program.

 *

 * @param  *pvParameters - Parameters point of task1

 *

 * @return  none

 */

void task1_task(void *pvParameters)

{

    TickType_t xLastWakeTime = 0;

    xLastWakeTime = xTaskGetTickCount();

    while(1)

    {

        if(GPIO_ReadOutputDataBit(GPIOA, GPIO_Pin_0) == Bit_RESET)

        {

            GPIO_SetBits(GPIOA, GPIO_Pin_0);

        }

        else

        {

            GPIO_ResetBits(GPIOA, GPIO_Pin_0);

        }

        vTaskDelayUntil( &xLastWakeTime, pdMS_TO_TICKS(1000));

    }

}

void task2_task(void *pvParameters)

{

    unsigned char StrTable[50] = {0};

    int16_t StrLength = 0;

    int16_t SendLength = 0;

    int16_t Count = 0;

    while(1)

    {

        vTaskDelay(pdMS_TO_TICKS(3000));

        Count++;

        StrLength = sprintf(StrTable,"StreamBuffer Test Count = %d",Count);

        SendLength = xStreamBufferSend(StreamBufferHandle,(void *)StrTable,StrLength,portMAX_DELAY);

        MYPRINT("Send: StrLength = %d  SendLength = %d\r\n",StrLength,SendLength);

    }

}

void task3_task(void *pvParameters)

{

    unsigned char StrTable[50] = {0};

    int16_t ReadLength = 0;

    while(1)

    {

        memset(StrTable,0x00,sizeof(StrTable));

        ReadLength = xStreamBufferReceive(StreamBufferHandle,(void *)StrTable,(sizeof(StrTable) - 1),portMAX_DELAY);

        MYPRINT("Read: ReadLength = %d String = %s\r",ReadLength,StrTable);

    }

}

/*********************************************************************

 * @fn      main

 *

 * @brief   Main program.

 *

 * @return  none

 */

int main(void)

{

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

    Delay_Init();

    USART_Printf_Init(115200);

    printf("SystemClk:%d\r\n",SystemCoreClock);

    printf("FreeRTOS Kernel Version:%s\r\n",tskKERNEL_VERSION_NUMBER);

    GPIO_Toggle_INIT();

    /* create two task */

    printf("uint8_t = %d , uint16_t = %d , size_t = %d \r\n",sizeof(uint8_t),sizeof(uint16_t),sizeof(size_t));

    StreamBufferHandle = xStreamBufferCreate(200,100);      //最大缓冲区为1000，大于50字节触发

    if(StreamBufferHandle != NULL)

    {

        printf("Creat Success \r\n");

    }

    printfSemaphoreHandle = xSemaphoreCreateBinary();

    xSemaphoreGive(printfSemaphoreHandle);

    xTaskCreate((TaskFunction_t )task1_task,

                            (const char*    )"task1",

                            (uint16_t       )TASK1_STK_SIZE,

                            (void*          )NULL,

                            (UBaseType_t    )TASK1_TASK_PRIO,

                            (TaskHandle_t*  )NULL);

    xTaskCreate((TaskFunction_t )task2_task,

                            (const char*    )"task2",

                            (uint16_t       )TASK2_STK_SIZE,

                            (void*          )NULL,

                            (UBaseType_t    )TASK2_TASK_PRIO,

                            (TaskHandle_t*  )&Task2Handle);

    xTaskCreate((TaskFunction_t )task3_task,

                            (const char*    )"task3",

                            (uint16_t       )TASK3_STK_SIZE,

                            (void*          )NULL,

                            (UBaseType_t    )TASK3_TASK_PRIO,

                            (TaskHandle_t*  )NULL);

    vTaskStartScheduler();

    while(1)

    {

        printf("shouldn't run at here!!\n");

    }

}

您好，可在每个打印函数打印时加个换行符（\）或在每个打印函数后面加个fflush(stdout)函数试一下

感谢3楼加上fflush(stdout)后确实可以了