目錄

• 前言
• 一、工程配置
• 二、串口DMA部分代碼
• • 1.源文件UART_DMA.c
  • 2.頭文件UART_DMA.h
  • 3.stm32f1xx_it.c的修改
  • 4.串口收發DMA測試
• 三、字符串數字提取代碼
• • 1.源文件NumAndStr.c:
  • 2.頭文件NumAndStr.h:
  • 3.測試:
• 四、Openmv / K210 發送、STM32接收測試
• 總結
• 修訂版本
• • UART_DMA.c
  • UART_DMA.h

平臺: STM32 Cube IDE

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前言

許多科創比賽中經常會有其他設備與STM32串口通訊的需求，比如可能需要Openmv / K210向STM32串口發送坐標的情況。下面我將介紹一種基于HAL庫的串口DMA不定長數據收發和數據解讀的方案。

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一、工程配置

1.選擇好芯片、配置好時鐘和debug模式后，使能要用到的串口。

2.使能該串口的收發收發DMA:

3.使能串口全局中斷，并生成工程文件。

二、串口DMA部分代碼

本部分代碼修改自xia0816大佬寫的《真正實現了STM32 HAL串口不定長數據的接收發送功能(DMA方式，不用限定單次接收長度和添加結束標志)》

1.源文件UART_DMA.c

#include "UART_DMA.h" #include <string.h> #include <stdarg.h> #include <stdio.h>uint8_t RxBuffer[UART_RX_BUF_SIZE] = {0}; uint8_t TxBuffer[UART_RX_BUF_SIZE] = {0}; uint8_t sendCompleteSign = 1; uint8_t TxLen = 0;void DataProcess(void) {//在這里加入數據處理的函數}//到USARTx_IRQHandler中添加，如: //void USART1_IRQHandler(void) //{ // /* USER CODE BEGIN USART1_IRQn 0 */ // if(__HAL_UART_GET_FLAG(&USB_Huart,UART_FLAG_IDLE)) // { // HAL_UART_IdleCallback(&USB_Huart); // } // // /* USER CODE END USART1_IRQn 0 */ // HAL_UART_IRQHandler(&huartx); //} void HAL_UART_IdleCallback(UART_HandleTypeDef *huart) {__HAL_UART_CLEAR_IDLEFLAG(huart);{HAL_UART_DMAStop(huart);ProcessData();StartUartRxDMA();} }void ProcessData() {uint32_t len = 0;//得到已經接收了多少個字節 = 總共要接收的字節數 - ?NDTR F1為CNDTR F4為NDTR#ifdef __STM32F1xx_HAL_Hlen = UART_RX_BUF_SIZE - USB_Huart.hdmarx->Instance->CNDTR;#define ProcessDataOK#endif#ifdef __STM32F4xx_HAL_Hlen = UART_RX_BUF_SIZE - USB_Huart.hdmarx->Instance->NDTR;#define ProcessDataOK#endif#ifndef ProcessDataOK增加所用芯片的版本#endifif(len > 0){if(sendCompleteSign == 1){ #if UART_RXTX_Switchmemset((void *)TxBuffer, 0, sizeof(TxBuffer));memcpy(TxBuffer, RxBuffer, len);TxLen = len;StartUartTxDMA(); //串口回顯 #endif{//在這里面加入數據處理的函數DataProcess();}}} }void USB_DMA_printf(const char *format,...) {uint32_t length;va_list args;va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);HAL_UART_Transmit_DMA(&USB_Huart,TxBuffer,length); }void USB_printf(const char *format,...) {uint32_t length;va_list args;va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);HAL_UART_Transmit(&USB_Huart,TxBuffer,length,0xFFFF); }/*** @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) {/* Prevent unused argument(s) compilation warning */ // UNUSED(huart);if(huart == &USB_Huart){sendCompleteSign = 1;}/* NOTE: This function should not be modified, when the callback is needed,the HAL_UART_TxCpltCallback could be implemented in the user file*/ }/*** @brief Rx 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_RxCpltCallback(UART_HandleTypeDef *huart) {/* Prevent unused argument(s) compilation warning */ // UNUSED(huart);if(huart == &USB_Huart){ProcessData();StartUartRxDMA();}/* NOTE: This function should not be modified, when the callback is needed,the HAL_UART_RxCpltCallback could be implemented in the user file*/ }uint8_t UartTxData(UART_HandleTypeDef *huart, uint8_t *buf, const uint32_t len) {HAL_StatusTypeDef status;uint8_t ret = 1;if(sendCompleteSign == 0 || len == 0){return 0;}sendCompleteSign = 0;status = HAL_UART_Transmit_DMA(huart, (uint8_t*)buf, len);if(HAL_OK != status){ret = 0;}return ret; }//啟動DMA發送 uint8_t StartUartTxDMA() {return UartTxData(&USB_Huart, TxBuffer, TxLen); }uint8_t UartRxData(UART_HandleTypeDef *huart, uint8_t *buf, const uint32_t len) {HAL_StatusTypeDef status;uint8_t ret = 1;status = HAL_UART_Receive_DMA(huart, (uint8_t*)buf, len);if(HAL_OK != status){ret = 0;}else{/* 開啟空閑接收中斷 */__HAL_UART_ENABLE_IT(huart, UART_IT_IDLE);}return ret; }//啟動DMA接收 uint8_t StartUartRxDMA() {return UartRxData(&USB_Huart, RxBuffer, UART_RX_BUF_SIZE); }

void ProcessData()中可能需要視所用芯片情況作部分修改，目前只測試過STM32F103VET6和STM32F411CEU6

//得到已經接收了多少個字節 = 總共要接收的字節數 - ?NDTR F1為CNDTR F4為NDTR#ifdef __STM32F1xx_HAL_Hlen = UART_RX_BUF_SIZE - USB_Huart.hdmarx->Instance->CNDTR;#define ProcessDataOK#endif#ifdef __STM32F4xx_HAL_Hlen = UART_RX_BUF_SIZE - USB_Huart.hdmarx->Instance->NDTR;#define ProcessDataOK#endif#ifndef ProcessDataOK增加所用芯片的版本#endif

2.頭文件UART_DMA.h

#ifndef UART_DMA_UART_DMA_H_ #define UART_DMA_UART_DMA_H_#include "main.h"extern UART_HandleTypeDef huart1; //修改為所用串口 #define USB_Huart huart1 //修改為所用串口#define UART_RX_BUF_SIZE 128#define UART_RXTX_Switch 1 //串口回顯開關/* 要在Cube中開串口全局中斷和收發DMA*/extern uint8_t RxBuffer[UART_RX_BUF_SIZE]; extern uint8_t TxBuffer[UART_RX_BUF_SIZE]; extern uint8_t TxLen;void USB_DMA_printf(const char *format,...); //printf DMA方式 void USB_printf(const char *format,...); //printf 普通方式 uint8_t UartTxData(UART_HandleTypeDef *huart, uint8_t *buf, const uint32_t len); uint8_t StartUartRxDMA(); //接收DMA初始化 uint8_t StartUartTxDMA(); //不需要自己調用 void ProcessData(); //在里面添加數據處理函數 void HAL_UART_IdleCallback(UART_HandleTypeDef *huart); //到USARTx_IRQHandler中添加#endif /* UART_DMA_UART_DMA_H_ */

3.stm32f1xx_it.c的修改

需要到stm32f1xx_it.c中的USARTx_IRQHandler添加幾句話

//... /* USER CODE BEGIN Includes */ #include "../UART_DMA/UART_DMA.h" /* USER CODE END Includes */ //... //... /*** @brief This function handles USART1 global interrupt.*/ void USART1_IRQHandler(void) {/* USER CODE BEGIN USART1_IRQn 0 */if(__HAL_UART_GET_FLAG(&USB_Huart,UART_FLAG_IDLE)){HAL_UART_IdleCallback(&USB_Huart);}/* USER CODE END USART1_IRQn 0 */HAL_UART_IRQHandler(&huart1);/* USER CODE BEGIN USART1_IRQn 1 *//* USER CODE END USART1_IRQn 1 */ } //...

4.串口收發DMA測試

(2022年1月25日補充)新版Cube MX有BUG，生成的初始化代碼順序有問題，見STM32 HAL串口DMA發送一直失敗 —— 攻城獅_鯊魚，故建議在生成的初始化代碼前手動

MX_DMA_Init();MX_USART1_UART_Init();

如

啟動串口DMA接收

//.../* USER CODE BEGIN 2 */StartUartRxDMA();/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){/* USER CODE END WHILE *//* USER CODE BEGIN 3 */}/* USER CODE END 3 */ //...

進入debug跑起來，將接收區緩存RxBuffer加入 現場表達式

//...uint8_t RxBuffer[UART_RX_BUF_SIZE] = {0};uint8_t TxBuffer[UART_RX_BUF_SIZE] = {0};uint8_t sendCompleteSign = 1;uint8_t TxLen = 0; //...

在ProcessData()中的該處打上斷點。

打開串口調試助手，選擇好參數后發送一段測試字符串，可以發現該字符串已成功存入緩沖區。

隨后又成功將數據通過DMA回顯

至此串口DMA收發已成功實現。

而源文件中附有的USB_DMA_printf()和USB_printf()分別為DMA方式的printf和普通的printf

void USB_DMA_printf(const char *format,...) {uint32_t length;va_list args;va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);HAL_UART_Transmit_DMA(&USB_Huart,TxBuffer,length); }void USB_printf(const char *format,...) {uint32_t length;va_list args;va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);HAL_UART_Transmit(&USB_Huart,TxBuffer,length,0xFFFF); }

效果如下:

為了進一步處理數據，下面介紹字符串數字提取的方案。

三、字符串數字提取代碼

改進型代碼見C語言字符串數字提取函數，支持負數、浮點數、科學記數法
實測double數據直接傳參數據會出錯，故采取了指針的方式。

1.源文件NumAndStr.c:

/** NumAndStr.c** Created on: Mar 15, 2021* Author: 乙酸氧鈹*/ #include "../NumAndStr/NumAndStr.h" #include <stdlib.h>int32_t str2int(uint8_t * str, uint8_t flag, uint8_t no) {uint8_t No = 1;uint8_t * Str = str;uint8_t NumTemp[TempIntLen];while(No!=no){if(*Str == flag)No++;Str++;}No = 0;while(*Str != flag && *Str != '\r' && *Str != '\n' && *Str != '\0' && No < (TempIntLen - 1)){NumTemp[No] = *Str;Str++;No++;}NumTemp[No] = '\0';return atoi(NumTemp); }void str2double(uint8_t * str, uint8_t flag, uint8_t no, double * Output) {uint8_t No = 1;uint8_t * Str = str;uint8_t NumTemp[TempDoubleLen];uint8_t NumTemp_int[TempDoubleLen];double OutputNum;while(No!=no){if(*Str == flag)No++;Str++;}No = 0;while(*Str != flag && *Str != '\r' && *Str != '\n' && *Str != '\0' && No < (TempDoubleLen - 1)){NumTemp[No] = *Str;Str++;No++;}NumTemp[No] = '\0';NumTemp[(TempDoubleLen - 1)] = 0;No = 0;while(NumTemp[NumTemp[(TempDoubleLen - 1)]] != '\0' && NumTemp[(TempDoubleLen - 1)] < (TempDoubleLen - 1)){if(NumTemp[NumTemp[(TempDoubleLen - 1)]] == '.'){NumTemp[(TempDoubleLen - 1)]++;NumTemp_int[(TempDoubleLen - 1)] = NumTemp[(TempDoubleLen - 1)];}NumTemp_int[No] = NumTemp[NumTemp[(TempDoubleLen - 1)]];No++;NumTemp[(TempDoubleLen - 1)]++;}NumTemp_int[No]='\0';NumTemp[(TempDoubleLen - 1)] = NumTemp_int[(TempDoubleLen - 1)]++;OutputNum = (double)atoi(NumTemp_int);while(NumTemp[NumTemp[(TempDoubleLen - 1)]] != '\0'){OutputNum /= 10;NumTemp[(TempDoubleLen - 1)] ++;}*Output = OutputNum; }

2.頭文件NumAndStr.h:

/** NumAndStr.h** Created on: Mar 15, 2021* Author: 乙酸氧鈹*/#ifndef NUMANDSTR_NUMANDSTR_H_ #define NUMANDSTR_NUMANDSTR_H_#include "main.h"#define TempDoubleLen 18 #define TempIntLen 11/* str:數字字符串首地址 flag:分隔符 no:第no個數字 從1開始計 Output: 小數存放地址*/ extern int32_t str2int(uint8_t * str, uint8_t flag, uint8_t no); extern void str2double(uint8_t * str, uint8_t flag, uint8_t no, double * Output);#endif /* NUMANDSTR_NUMANDSTR_H_ */

str:數字字符串首地址
flag:分隔符
no:第no個數字 從1開始計
Output: 小數存放地址

3.測試:

修改UART_DMA.c中的DataProcess()函數

#include "../NumAndStr/NumAndStr.h" //包含頭文件int32_t a,b,c; double d,e,f; void DataProcess(void) {//在這里加入數據處理的函數a = str2int(RxBuffer, ' ', 1);b = str2int(RxBuffer, ' ', 2);c = str2int(RxBuffer, ' ', 3);str2double(RxBuffer, ' ', 4, &d);str2double(RxBuffer, ' ', 5, &e);str2double(RxBuffer, ' ', 6, &f); }

進入debug模式，監視變量a、b、c、d、e、f，使用串口調試助手再次發送一段測試字符串
效果如圖所示:

可以看到六個數據都已成功存入對應的變量中，并成功回顯。

且多次測試都能成功解讀

四、Openmv / K210 發送、STM32接收測試

(示例) 平臺: MaixPy IDE、K210 Maix Bit

K210 串口測試程序
延時500ms時

import utime from board import board_info from Maix import freq from fpioa_manager import fm from machine import UARTimport randomfm.register(9,fm.fpioa.UART1_TX) fm.register(10,fm.fpioa.UART1_RX) UART_USB = UART(UART.UART1, 115200, 8, None, 1, timeout = 1000, read_buf_len = 128)while(True):Tube_X = random.randint(-200,200)Tube_Y = random.randint(-200,200)Tube_Angle = random.random()print('%d %d %f'%(Tube_X, Tube_Y, Tube_Angle))UART_USB.write('%d %d %f\r\n'%(Tube_X, Tube_Y, Tube_Angle))utime.sleep_ms(500)

修改UART_DMA.c中的DataProcess()函數

int32_t Tube_X = 0, Tube_Y = 0; double Tube_Angle = 0; void DataProcess(void) {//在這里加入數據處理的函數Tube_X = str2int(RxBuffer, ' ', 1);Tube_Y = str2int(RxBuffer, ' ', 2);str2double(RxBuffer, ' ', 3, &Tube_Angle); }

進入debug，如圖所示，數據提取成功

延時15ms時

#... while(True):Tube_X = random.randint(-200,200)Tube_Y = random.randint(-200,200)Tube_Angle = random.random()print('%d %d %f'%(Tube_X, Tube_Y, Tube_Angle))UART_USB.write('%d %d %f\r\n'%(Tube_X, Tube_Y, Tube_Angle))utime.sleep_ms(15)#...

總結

本文介紹了一種STM32 串口DMA收發并解讀的方案，對CPU要求較小，只需自己選擇分隔符號，不需要設計復雜的通信協議就能得到對應位置的數據，應該可以應用到使用STM32的多種科創比賽項目中去。

修訂版本

UART_DMA.c

/** UART_DMA.c** Created on: Mar 14, 2021* Author: Royic*/ #include "UART_DMA.h" #include <string.h> #include <stdarg.h> #include <stdio.h>uint8_t RxBuffer[UART_RX_BUF_SIZE] = {0}; uint8_t TxBuffer[UART_RX_BUF_SIZE] = {0}; uint8_t sendCompleteSign = 1; uint8_t TxLen = 0; uint8_t USE_UART_DMA = 0;void DataProcess(UART_HandleTypeDef *huart, uint32_t Len) {//在這里加入數據處理的函數 #ifdef USB_Huart_1if(huart == &USB_Huart_1){;} #endif #ifdef USB_Huart_2if(huart == &USB_Huart_2){;} #endif }//到USARTx_IRQHandler中添加，如: //void USART1_IRQHandler(void) //{ // /* USER CODE BEGIN USART1_IRQn 0 */ // if(__HAL_UART_GET_FLAG(&USB_Huart_1,UART_FLAG_IDLE)) // { // HAL_UART_IdleCallback(&USB_Huart_1); // } // // /* USER CODE END USART1_IRQn 0 */ // HAL_UART_IRQHandler(&huartx); //} void HAL_UART_IdleCallback(UART_HandleTypeDef *huart) {__HAL_UART_CLEAR_IDLEFLAG(huart);{HAL_UART_DMAStop(huart);ProcessData(huart);StartUartRxDMA(huart);} }void ProcessData(UART_HandleTypeDef *huart) {uint32_t len = 0;len = UART_RX_BUF_SIZE - __HAL_DMA_GET_COUNTER(huart->hdmarx);if(len > 0){if(sendCompleteSign == 1){ #if UART_RXTX_Switchmemset((void *)TxBuffer, 0, sizeof(TxBuffer));memcpy(TxBuffer, RxBuffer, len);TxLen = len;StartUartTxDMA(huart); //串口回顯 #endif}{//在這里面加入數據處理的函數DataProcess(huart, len);}} }void USB_DMA_printf(UART_HandleTypeDef *huart, const char *format,...) {uint32_t length;va_list args;va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);HAL_UART_Transmit_DMA(huart,TxBuffer,length); }void USB_printf(UART_HandleTypeDef *huart, const char *format,...) {uint32_t length;va_list args;va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);HAL_UART_Transmit(huart,TxBuffer,length,0xFFFF); }/*** @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) {/* Prevent unused argument(s) compilation warning */sendCompleteSign = 1;/* NOTE: This function should not be modified, when the callback is needed,the HAL_UART_TxCpltCallback could be implemented in the user file*/ }/*** @brief Rx 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_RxCpltCallback(UART_HandleTypeDef *huart) {/* Prevent unused argument(s) compilation warning */ProcessData(huart);StartUartRxDMA(huart);/* NOTE: This function should not be modified, when the callback is needed,the HAL_UART_RxCpltCallback could be implemented in the user file*/ }uint8_t UartTxData(UART_HandleTypeDef *huart, uint8_t *buf, const uint32_t len) {HAL_StatusTypeDef status;uint8_t ret = 1;if(sendCompleteSign == 0 || len == 0){return 0;}sendCompleteSign = 0;status = HAL_UART_Transmit_DMA(huart, (uint8_t*)buf, len);if(HAL_OK != status){ret = 0;}return ret; }//啟動DMA發送 uint8_t StartUartTxDMA(UART_HandleTypeDef *huart) {return UartTxData(huart, TxBuffer, TxLen); }uint8_t UartRxData(UART_HandleTypeDef *huart, uint8_t *buf, const uint32_t len) {HAL_StatusTypeDef status;uint8_t ret = 1;status = HAL_UART_Receive_DMA(huart, (uint8_t*)buf, len);if(HAL_OK != status){ret = 0;}else{/* 開啟空閑接收中斷 */__HAL_UART_ENABLE_IT(huart, UART_IT_IDLE);}return ret; }//啟動DMA接收 uint8_t StartUartRxDMA(UART_HandleTypeDef *huart) {USE_UART_DMA = 1;return UartRxData(huart, RxBuffer, UART_RX_BUF_SIZE); }

UART_DMA.h

/** UART_DMA.h** Created on: Mar 14, 2021* Author: Royic*/#ifndef UART_DMA_UART_DMA_H_ #define UART_DMA_UART_DMA_H_#include "main.h"#define USB_Huart_1 huart1 //修改為所用串口 extern UART_HandleTypeDef USB_Huart_1;#define USB_Huart_2 huart2 //修改為所用串口 extern UART_HandleTypeDef USB_Huart_2;#define UART_RX_BUF_SIZE 128#define UART_RXTX_Switch 0 //串口回顯開關 //#define UART_DMA_Switch 0 /* 要在Cube中開串口全局中斷和收發DMA*/extern uint8_t RxBuffer[UART_RX_BUF_SIZE]; extern uint8_t TxBuffer[UART_RX_BUF_SIZE]; extern uint8_t TxLen; extern uint8_t USE_UART_DMA;void USB_DMA_printf(UART_HandleTypeDef *huart, const char *format,...); //printf DMA方式 void USB_printf(UART_HandleTypeDef *huart, const char *format,...); //printf 普通方式 uint8_t UartTxData(UART_HandleTypeDef *huart, uint8_t *buf, const uint32_t len); uint8_t StartUartRxDMA(UART_HandleTypeDef *huart); //接收DMA初始化 uint8_t StartUartTxDMA(UART_HandleTypeDef *huart); //不需要自己調用 void ProcessData(UART_HandleTypeDef *huart); //在里面添加數據處理函數 void HAL_UART_IdleCallback(UART_HandleTypeDef *huart); //到USARTx_IRQHandler中添加#endif /* UART_DMA_UART_DMA_H_ */

總結

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