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[问答]

UART的DMA操作方式是什么

UART的DMA操作方式是什么?

如何对STM32F103 UART进行帧数据接收呢?

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陈秀珍

2021-12-13 14:42:12
  本文主要记录UART DMA操作方式,同时对STM32F103 UART驱动抽象出来实现帧数据接收
  1、MDK工程目录(创建工程方式略)
  
  main.c内容如下
  运行后的结果是UART收到数据立即通过TX发送出去,同时LED状态反转一次
  #include 《stdio.h》
  #include “stm32f10x.h”
  #include “platform.h”
  unsigned char led_count = 0;
  void LED_Init(void){
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
  }
  void uart_recv_str(UART_TypeDef *p, uint8_t *pbuf, uint16_t len){
  UART_ApiStructure.send_str(p, pbuf, len);
  GPIO_WriteBit(GPIOB, GPIO_Pin_9, (++led_count & 0x01) ? Bit_SET : Bit_RESET);
  }
  int main(void){
  LED_Init();
  UART_ApiStructure.config(&UART_TypeDef_param, uart_recv_str);
  UART_ApiStructure.send_str(&UART_TypeDef_param, (uint8_t *)“uart init okrn”, 14);
  for(;;){}
  }
  uart.h
  #ifndef __UART_H
  #define __UART_H
  typedef void (*pfunc_uart_gpio_init)(void);
  /**
  * @addtogroup 串口参数定义
  * @{
  */
  /** UART 数据处理设置 */
  typedef struct{
  uint8_t *tx_buf; /*!《 发送数据缓存 */
  uint8_t *rx_buf; /*!《 接收数据缓存 */
  uint16_t tx_buf_len_max; /*!《 发送数据最大缓存空间大小 */
  uint16_t rx_buf_len_max; /*!《 接收数据最大缓存空间大小 */
  uint16_t rx_tail; /*!《 接收数据缓存尾标识 */
  uint16_t rx_head; /*!《 接收数据缓存头标识 */
  }UART_UserParam;
  /** DMA 参数设置 */
  typedef struct{
  uint8_t irq_tx; /*!《 发送通道中断号 */
  uint8_t irq_rx; /*!《 接收通道中断号 */
  DMA_Channel_TypeDef *channel_tx; /*!《 发送通道 */
  DMA_Channel_TypeDef *channel_rx; /*!《 接收通道 */
  uint32_t TX_IT_FLAG_TCx; /*!《 发送完成中断标志 */
  uint32_t RX_IT_FLAG_TCx; /*!《 接收完成中断标志 */
  }DMA_Param;
  /** UART 参数设置 */
  typedef struct{
  uint32_t baud; /*!《 波特率参数 */
  pfunc_uart_gpio_init pfunc_gpio_init; /*!《 指向串口GPIO初始化函数指针 */
  USART_TypeDef* USARTx; /*!《 使用串口号 */
  uint8_t USARTx_IRQn; /*!《 串口接收中断号 */
  DMA_Param *DMAx; /*!《 DMA参数指针 */
  UART_UserParam *user; /*!《 UART数据处理指针 */
  }UART_TypeDef;
  /**
  * @}
  */
  /**
  * @addtogroup API 接口定义
  */
  typedef void (*pfunc_uart_rsend_str)(UART_TypeDef *p, uint8_t *pbuf, uint16_t len);
  typedef uint8_t (*pfunc_uart_config)(UART_TypeDef *p, pfunc_uart_rsend_str cb);
  typedef struct{
  pfunc_uart_config config; /*!《 初始化串口 */
  pfunc_uart_rsend_str send_str; /*!《 发送数据 */
  pfunc_uart_rsend_str recv_cb; /*!《 接收数据 */
  }UART_ApiDef;
  extern UART_ApiDef UART_ApiStructure;
  /**
  * @}
  */
  #ifdef USE_PRINTF
  extern int __printf(const char *fmt, 。..);
  #else
  #define __printf(。..)
  #endif
  #endif
  uart.c
  /**
  * @file uart.c USART 驱动程序
  *
  * @author T0213-ZH
  * @date 2018.06.13
  */
  #include “platform.h”
  /**
  * @brief 配置USART参数
  * @param p: 指向串口参数指针
  * @param cb: 用于接收数据回调函数指针
  *
  * @retval 0-成功,1-已初始过了,2-未设置GPIO初始函数, 3-串口组参数不匹配
  */
  static uint8_t uart_init(UART_TypeDef *p, pfunc_uart_rsend_str cb){
  USART_InitTypeDef USART_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  DMA_InitTypeDef DMA_InitStructure;
  //if(g_uart_param) return 1;
  if(!p-》pfunc_gpio_init) return 2;
  if(cb)
  UART_ApiStructure.recv_cb = cb;
  //g_uart_param = p;
  p-》pfunc_gpio_init();
  if(p-》USARTx == USART1){
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
  }else if(p-》USARTx == USART2){
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
  }else if(p-》USARTx == USART3){
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
  }else{
  return 3;
  }
  USART_InitStructure.USART_BaudRate = p-》baud;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(p-》USARTx, &USART_InitStructure);
  USART_Cmd(p-》USARTx, ENABLE);
  USART_ClearFlag(p-》USARTx, USART_FLAG_TC); //注:避免首字符丢掉现象
  USART_ITConfig(p-》USARTx, USART_IT_IDLE, ENABLE);
  NVIC_InitStructure.NVIC_IRQChannel = p-》USARTx_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  USART_DMACmd(p-》USARTx, USART_DMAReq_Tx, ENABLE);
  USART_DMACmd(p-》USARTx, USART_DMAReq_Rx, ENABLE);
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
  //DMA TX Config
  DMA_DeInit(p-》DMAx-》channel_tx);
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)(&p-》USARTx-》DR);
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)p-》user-》tx_buf;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
  DMA_InitStructure.DMA_BufferSize = p-》user-》tx_buf_len_max;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
  DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init(p-》DMAx-》channel_tx, &DMA_InitStructure);
  //DMA_Cmd(p-》DMAx-》channel_tx, ENABLE)
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
  NVIC_InitStructure.NVIC_IRQChannel = p-》DMAx-》irq_tx;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  //DMA RX Config
  DMA_DeInit(p-》DMAx-》channel_rx);
  DMA_InitStructure.DMA_BufferSize = p-》user-》rx_buf_len_max;;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)p-》user-》rx_buf;
  DMA_Init(p-》DMAx-》channel_rx, &DMA_InitStructure);
  DMA_Cmd(p-》DMAx-》channel_rx, ENABLE);
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
  NVIC_InitStructure.NVIC_IRQChannel = p-》DMAx-》irq_rx;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  DMA_ITConfig(p-》DMAx-》channel_tx, DMA_IT_TC, ENABLE);
  DMA_ITConfig(p-》DMAx-》channel_rx, DMA_IT_TC, ENABLE);
  return 0;
  }
  /**
  * @brief 发送数据接口
  * @param p: 指向发送数据缓存指针
  * @param len: 数据长度
  *
  * @retval none
  */
  static void uart_send_str(UART_TypeDef *p, uint8_t *pbuf, uint16_t len){
  if(!len) return;
  uint16_t i;
  for(i=0; i《len; i++){
  p-》user-》tx_buf[i] = *pbuf++;
  }
  while(DMA_GetFlagStatus(p-》DMAx-》TX_IT_FLAG_TCx) == SET);
  DMA_SetCurrDataCounter(p-》DMAx-》channel_tx, len);
  DMA_Cmd(p-》DMAx-》channel_tx, ENABLE);
  }
  /**
  * @brief 接收数据接口,中断触发
  *
  * @retval none
  */
  static void uart_recv_len(UART_TypeDef *p){
  p-》user-》rx_head = p-》user-》rx_buf_len_max - DMA_GetCurrDataCounter(p-》DMAx-》channel_rx);
  if(p-》user-》rx_tail != p-》user-》rx_head){
  uint16_t i = 0;
  uint8_t buf[p-》user-》rx_buf_len_max];
  uint16_t head = p-》user-》rx_head;
  do{
  buf[i++] = p-》user-》rx_buf[p-》user-》rx_tail++];
  if(p-》user-》rx_tail == p-》user-》rx_buf_len_max)
  p-》user-》rx_tail = 0;
  }while(p-》user-》rx_tail != head);
  if(UART_ApiStructure.recv_cb){
  UART_ApiStructure.recv_cb(p, buf, i);
  }
  //uart_send_str(buf, i);
  }
  }
  /**
  * @brief UART 接口函数
  */
  UART_ApiDef UART_ApiStructure = {
  .config = uart_init, /*!《 指向串口参数配置接口函数指针 */
  .send_str = uart_send_str, /*!《 指向串口发送字符串接口函数指针 */
  .recv_cb = 0,
  };
  void uart_tx_irq(UART_TypeDef *p){
  if(DMA_GetITStatus(p-》DMAx-》TX_IT_FLAG_TCx) == SET){
  DMA_Cmd(p-》DMAx-》channel_tx, DISABLE);
  DMA_ClearITPendingBit(p-》DMAx-》TX_IT_FLAG_TCx);
  }
  }
  void uart_rx_irq(UART_TypeDef *p){
  if(DMA_GetITStatus(p-》DMAx-》RX_IT_FLAG_TCx) == SET){
  DMA_ClearITPendingBit(p-》DMAx-》RX_IT_FLAG_TCx);
  }
  }
  void uart_irq(UART_TypeDef *p){
  if(USART_GetITStatus(p-》USARTx, USART_IT_IDLE) != RESET){
  USART_ReceiveData(p-》USARTx);
  USART_ClearITPendingBit(p-》USARTx, USART_IT_IDLE);
  uart_recv_len(p);
  }
  }
  #ifdef USE_PRINTF
  int __fputc(unsigned char ch, unsigned char *f){
  /* Place your implementation of fputc here */
  /* e.g. write a character to the USART */
  USART_SendData(USART1, (uint8_t) ch);
  /* Loop until the end of transmission */
  while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)
  {}
  return ch;
  }
  #endif
  platform.c
  #include “platform.h”
  extern void uart_tx_irq(UART_TypeDef *p);
  extern void uart_rx_irq(UART_TypeDef *p);
  extern void uart_irq(UART_TypeDef *p);
  void USART_GpioInit(void){
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  }
  /**
  * @addtogroup
  * @{
  */
  #define UART_TX_BUF_MAX (256)
  #define UART_RX_BUF_MAX (256)
  uint8_t uart_tx_buf[UART_TX_BUF_MAX];
  uint8_t uart_rx_buf[UART_RX_BUF_MAX];
  DMA_Param dma_param = {
  .irq_tx = DMA1_Channel4_IRQn,
  .irq_rx = DMA1_Channel5_IRQn,
  .channel_tx = DMA1_Channel4,
  .channel_rx = DMA1_Channel5,
  .TX_IT_FLAG_TCx = DMA1_IT_TC4,
  .RX_IT_FLAG_TCx = DMA1_IT_TC5,
  };
  /** UART */
  UART_UserParam uart_param = {
  .tx_buf = uart_tx_buf,
  .rx_buf = uart_rx_buf,
  .tx_buf_len_max = UART_TX_BUF_MAX,
  .rx_buf_len_max = UART_RX_BUF_MAX,
  .rx_tail = 0,
  .rx_head = 0,
  };
  /** UART */
  UART_TypeDef UART_TypeDef_param = {
  .baud = 115200,
  .pfunc_gpio_init = USART_GpioInit,
  .USARTx = USART1,
  .USARTx_IRQn = USART1_IRQn,
  .DMAx = &dma_param,
  .user = &uart_param,
  };
  void DMA1_Channel4_IRQHandler(void){
  uart_tx_irq(&UART_TypeDef_param);
  }
  void DMA1_Channel5_IRQHandler(void){
  uart_rx_irq(&UART_TypeDef_param);
  }
  void USART1_IRQHandler(void){
  uart_irq(&UART_TypeDef_param);
  }
  /**
  * @}
  */
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