STM32CubeMx启动串口调试功能Printf调试

##　概述

项目中往往需要调试信息，调试stm32的时候，需要标准库里面的printf函数。在keil MDK环境下重定向printf与keil C51不同，由于本人使用了STM32CubeMX生成工程模板，HAL_USART_Transmit函数即是模板里串口输出的函数。由于printf最终是调用fputc输出数据，fputc是一个弱引用(weak)函数，覆写即可重定向printf。

代码清单

/* USER CODE BEGIN Includes */

#include "FreeRTOS.h"

#include "task.h"

#include "queue.h"

#include

/* USER CODE END Includes */

/* USER CODE BEGIN PV */

/* Private variables ---------------------------------------------------------*/

#ifdef __GNUC__

#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)

#else

#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)

#endif

PUTCHAR_PROTOTYPE

{

HAL_UART_Transmit(&huart1 , (uint8_t *)&ch, 1, 0xFFFF);

return ch;

}

/* USER CODE END PV */

####　华丽的分界线

例子：

硬件平台：stm32F407Zet6

软件平台：stm32cubeMX 4.7+MDK5.14

电路连接：PA9,PA10

第一步、通过Stm32CubeMX图形界面创建Keil工程

需要配置的地方是：

第二章配置图：

在这里可以修改串口工作的一下参数，软件就可以生成配置好的工程，不需要亲自去配置这些了。

第二步。打开工程，编写代码，验证

代码清单

/* USER CODE BEGIN PV */

#include "stdio.h"

#ifdef __GNUC__

#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)

#else

#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)

#endif /* __GNUC__ */

PUTCHAR_PROTOTYPE

{

HAL_UART_Transmit(&huart1 , (uint8_t *)&ch, 1, 0xFFFF);

return ch;

}

/* USER CODE END PV */

这段程序为了可以使用printf（）函数，对字符输出函数进行了重定向，这样我们就可以在程序中使用printf函数进行输出了，这里使用的是查询发送方式，有超时控制的。接下来来看中断方式的。

代码清单

/**

  * @brief  This function handles UART interrupt request.

  * @param  huart: pointer to a UART_HandleTypeDef structure that contains

  *                the configuration information for the specified UART module.

  * @retval None

  */

void HAL_UART_IRQHandler(UART_HandleTypeDef *huart)

{

  uint32_t tmp1 = 0, tmp2 = 0;

  tmp1 = __HAL_UART_GET_FLAG(huart, UART_FLAG_PE);

  tmp2 = __HAL_UART_GET_IT_SOURCE(huart, UART_IT_PE);  

  /* UART parity error interrupt occurred ------------------------------------*/

  if((tmp1 != RESET) && (tmp2 != RESET))

  { 

    __HAL_UART_CLEAR_PEFLAG(huart);

    huart->ErrorCode |= HAL_UART_ERROR_PE;

  }

  tmp1 = __HAL_UART_GET_FLAG(huart, UART_FLAG_FE);

  tmp2 = __HAL_UART_GET_IT_SOURCE(huart, UART_IT_ERR);

  /* UART frame error interrupt occurred -------------------------------------*/

  if((tmp1 != RESET) && (tmp2 != RESET))

  { 

    __HAL_UART_CLEAR_FEFLAG(huart);

    huart->ErrorCode |= HAL_UART_ERROR_FE;

  }

  tmp1 = __HAL_UART_GET_FLAG(huart, UART_FLAG_NE);

  tmp2 = __HAL_UART_GET_IT_SOURCE(huart, UART_IT_ERR);

  /* UART noise error interrupt occurred -------------------------------------*/

  if((tmp1 != RESET) && (tmp2 != RESET))

  { 

    __HAL_UART_CLEAR_NEFLAG(huart);

    huart->ErrorCode |= HAL_UART_ERROR_NE;

  }

  tmp1 = __HAL_UART_GET_FLAG(huart, UART_FLAG_ORE);

  tmp2 = __HAL_UART_GET_IT_SOURCE(huart, UART_IT_ERR);

  /* UART Over-Run interrupt occurred ----------------------------------------*/

  if((tmp1 != RESET) && (tmp2 != RESET))

  { 

    __HAL_UART_CLEAR_OREFLAG(huart);

    huart->ErrorCode |= HAL_UART_ERROR_ORE;

  }

  tmp1 = __HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE);

  tmp2 = __HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE);

  /* UART in mode Receiver ---------------------------------------------------*/

  if((tmp1 != RESET) && (tmp2 != RESET))

  { 

    UART_Receive_IT(huart);

  }

  tmp1 = __HAL_UART_GET_FLAG(huart, UART_FLAG_TXE);

  tmp2 = __HAL_UART_GET_IT_SOURCE(huart, UART_IT_TXE);

  /* UART in mode Transmitter ------------------------------------------------*/

  if((tmp1 != RESET) && (tmp2 != RESET))

  {

    UART_Transmit_IT(huart);

  }

  tmp1 = __HAL_UART_GET_FLAG(huart, UART_FLAG_TC);

  tmp2 = __HAL_UART_GET_IT_SOURCE(huart, UART_IT_TC);

  /* UART in mode Transmitter end --------------------------------------------*/

  if((tmp1 != RESET) && (tmp2 != RESET))

  {

    UART_EndTransmit_IT(huart);

  }

  if(huart->ErrorCode != HAL_UART_ERROR_NONE)

  {

    /* Set the UART state ready to be able to start again the process */

    huart->State = HAL_UART_STATE_READY;

    HAL_UART_ErrorCallback(huart);

  }  

}

这个函数中查询了所有可能发生的中断。用到的中断是发送完成中断，就找到了UART_EndTransmit_IT(huart);再跳进去看看:

代码清单

/**

  * @brief  Wraps up transmission in non blocking mode.

  * @param  huart: pointer to a UART_HandleTypeDef structure that contains

  *                the configuration information for the specified UART module.

  * @retval HAL status

  */

static HAL_StatusTypeDef UART_EndTransmit_IT(UART_HandleTypeDef *huart)

{

  /* Disable the UART Transmit Complete Interrupt */    

  __HAL_UART_DISABLE_IT(huart, UART_IT_TC);

  /* Check if a receive process is ongoing or not */

  if(huart->State == HAL_UART_STATE_BUSY_TX_RX) 

  {

    huart->State = HAL_UART_STATE_BUSY_RX;

  }

  else

  {

    /* Disable the UART Parity Error Interrupt */

    __HAL_UART_DISABLE_IT(huart, UART_IT_PE);

    /* Disable the UART Error Interrupt: (Frame error, noise error, overrun error) */

    __HAL_UART_DISABLE_IT(huart, UART_IT_ERR);

    huart->State = HAL_UART_STATE_READY;

  }

  HAL_UART_TxCpltCallback(huart);

  return HAL_OK;

}

这个函数在确定中断发生了之后调用了，HAL_UART_TxCpltCallback(huart);从函数名上可以看出，这是个回调函数，就是留给上层来实现的函数，由这个函数的实现不同，来实现不同的功能。这里来实现这个函数，让它在中断发生的时候吧USART1Ready置为SET；代码修改如下:

代码清单

/* USER CODE BEGIN PV */

#include "stdio.h"

#ifdef __GNUC__

#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)

#else

#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)

#endif /* __GNUC__ */

__IO ITStatus USART1Ready = RESET;

PUTCHAR_PROTOTYPE

{

HAL_UART_Transmit_IT(&huart1 , (uint8_t *)&ch, 1);

while (USART1Ready != SET)

  {

  }

USART1Ready = RESET;

return ch;

}

/* USER CODE END PV */

这是重定向函数的修改，启动发送之后，等待发送完成。重新实现的回调函数如下图所示：

/**

  * @brief  Tx Transfer completed callbacks.

  * @param  huart: pointer to a UART_HandleTypeDef structure that contains

  *                the configuration information for the specified UART module.

  * @retval None

  */

void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)

{

  /* NOTE: This function Should not be modified, when the callback is needed,

           the HAL_UART_TxCpltCallback could be implemented in the user file

   */ 

USART1Ready = SET;

}

最后，编译，下载验证代码！