Stm32使用Usart代码例子

最新推荐文章于 2025-10-29 15:04:55 发布

最新推荐文章于 2025-10-29 15:04:55 发布 · 898 阅读

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#单片机 #stm32 #usart #f3 #discovery

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本文介绍了STM32中USART接口的三种实现方式：非中断方式、中断方式及DMA方式，并提供了详细的代码示例。

stm32使用库函数编写USART还是很方便的，现在转几个例子：

/***************************************
转载请注明出处：tedeum.iteye.com
****************************************/

首先是不使用中断的方法使用usart1,管脚pa9,pa10，此方法已在f3discovery上验证通过，来源：https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=%2Fpublic%2FSTe2ecommunities%2Fmcu%2FLists%2Fcortex_mx_stm32%2Fusart%20code&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=524

// STM32 USART1 (Tx PA.9, Rx PA.10) STM32F3-Discovery - sourcer32@gmail.com
 
#include "stm32f30x.h"
 
/**************************************************************************************/
  
void RCC_Configuration(void)
{
  /* Enable GPIO clock */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
 
  /* Enable USART clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
}
 
/**************************************************************************************/
  
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
 
  /* Connect PA9 to USART1_Tx */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_7);
 
  /* Connect PA10 to USART1_Rx */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_7);
 
  /* Configure USART Tx as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
 
  /* Configure USART Rx as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
}
 
/**************************************************************************************/
 
void USART1_Configuration(void)
{
  USART_InitTypeDef USART_InitStructure;
 
  /* USART resources configuration (Clock, GPIO pins and USART registers) ----*/
  /* USART configured as follow:
        - BaudRate = 115200 baud
        - Word Length = 8 Bits
        - One Stop Bit
        - No parity
        - Hardware flow control disabled (RTS and CTS signals)
        - Receive and transmit enabled
  */
  USART_InitStructure.USART_BaudRate = 115200;
  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 configuration */
  USART_Init(USART1, &USART_InitStructure);
 
  /* Enable USART */
  USART_Cmd(USART1, ENABLE);
}
 
/**************************************************************************************/
 
int main(void)
{
  RCC_Configuration();
  
  GPIO_Configuration();
  
  USART1_Configuration();
  
  while(1)
  {
    while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET); // Wait for Empty
  
    USART_SendData(USART1, 0x49); // Send 'I'
  }
  
  while(1); // Don't want to exit
}
 
/**************************************************************************************/
 
#ifdef  USE_FULL_ASSERT
 
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
 
  /* Infinite loop */
  while (1)
  {
  }
}
#endif

接下来是使用中断的方法，使用USART3，管脚pd8，pd9，来源：https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/STM32F4%20USART%20receive%20problem&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=124

// STM32 USART IRQ TX/RX Loop (USART3 Tx PD.8, Rx PD.9) STM32F4 Discovery - sourcer32@gmail.com
 
#include "stm32f4_discovery.h"
 
volatile char StringLoop[] = "The quick brown fox jumps over the lazy dog\r\n";
 
/**************************************************************************************/
 
void RCC_Configuration(void)
{
  /* --------------------------- System Clocks Configuration -----------------*/
  /* USART3 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
 
  /* GPIOD clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
}
 
/**************************************************************************************/
 
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
 
  /*-------------------------- GPIO Configuration ----------------------------*/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOD, &GPIO_InitStructure);
 
  /* Connect USART pins to AF */
  GPIO_PinAFConfig(GPIOD, GPIO_PinSource8, GPIO_AF_USART3);
  GPIO_PinAFConfig(GPIOD, GPIO_PinSource9, GPIO_AF_USART3);
}
 
/**************************************************************************************/
 
void USART3_Configuration(void)
{
    USART_InitTypeDef USART_InitStructure;
 
  /* USARTx configuration ------------------------------------------------------*/
  /* USARTx configured as follow:
        - BaudRate = 9600 baud
        - Word Length = 8 Bits
        - One Stop Bit
        - No parity
        - Hardware flow control disabled (RTS and CTS signals)
        - Receive and transmit enabled
  */
  USART_InitStructure.USART_BaudRate = 9600;
  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(USART3, &USART_InitStructure);
 
  USART_Cmd(USART3, ENABLE);

 USART_ITConfig(USART3, USART_IT_TXE, ENABLE);

 USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);
}
 
/**************************************************************************************/
 
void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
 
  /* Configure the NVIC Preemption Priority Bits */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
 
  /* Enable the USART3 Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}
 
/**************************************************************************************/
 
void USART3_IRQHandler(void)
{
  static int tx_index = 0;
  static int rx_index = 0;
 
  if (USART_GetITStatus(USART3, USART_IT_TXE) != RESET) // Transmit the string in a loop
  {
    USART_SendData(USART3, StringLoop[tx_index++]);
 
    if (tx_index >= (sizeof(StringLoop) - 1))
      tx_index = 0;
  }
 
  if (USART_GetITStatus(USART3, USART_IT_RXNE) != RESET) // Received characters modify string
  {
    StringLoop[rx_index++] = USART_ReceiveData(USART3);
 
    if (rx_index >= (sizeof(StringLoop) - 1))
      rx_index = 0;
  }
}
 
/**************************************************************************************/
 
int main(void)
{
    RCC_Configuration();
 
    GPIO_Configuration();
 
    NVIC_Configuration();
 
  USART3_Configuration();
 
  while(1); // Don't want to exit
}
 
/**************************************************************************************/

最后，是使用DMA的方法，使用usart5，管脚：pc12，pd2，来源：https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/DMA%20Memory%20To%20UART5&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=760

// STM32 UART5 DMA TX (Tx PC.12, Rx PD.2) STM32F4 Discovery - sourcer32@gmail.com
 
#include "stm32f4_discovery.h"
 
/**************************************************************************************/
 
void RCC_Configuration(void)
{
  /* --------------------------- System Clocks Configuration -----------------*/
  /* UART5 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART5, ENABLE);
 
  /* GPIOC and GPIOD clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_GPIOD, ENABLE);
 
  /* DMA1 clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
}
 
/**************************************************************************************/
 
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
 
  /*-------------------------- GPIO Configuration ----------------------------*/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12; // PC.12 UART5_TX, potential clash SDIN CS43L22
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);
 
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; // PD.2 UART5_RX
  GPIO_Init(GPIOD, &GPIO_InitStructure);
 
  /* Connect USART pins to AF */
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource12, GPIO_AF_UART5);
  GPIO_PinAFConfig(GPIOD, GPIO_PinSource2, GPIO_AF_UART5);
}
 
/**************************************************************************************/
 
void UART5_Configuration(void)
{
    USART_InitTypeDef USART_InitStructure;
 
  /* USARTx configuration ------------------------------------------------------*/
  /* USARTx configured as follow:
        - BaudRate = 115200 baud
        - Word Length = 8 Bits
        - One Stop Bit
        - No parity
        - Hardware flow control disabled (RTS and CTS signals)
        - Receive and transmit enabled
  */
  USART_InitStructure.USART_BaudRate = 115200;
  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(UART5, &USART_InitStructure);
 
  USART_Cmd(UART5, ENABLE);
}
 
/**************************************************************************************/
 
char Buffer[] = "The quick brown fox jumps over the lazy dog\r\n";
 
void DMA_Configuration(void)
{
  DMA_InitTypeDef  DMA_InitStructure;
 
  DMA_DeInit(DMA1_Stream7);
 
  DMA_InitStructure.DMA_Channel = DMA_Channel_4;
  DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral; // Transmit
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)Buffer;
  DMA_InitStructure.DMA_BufferSize = (uint16_t)sizeof(Buffer) - 1;
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&UART5->DR;
  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_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;
  DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;
  DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
 
  DMA_Init(DMA1_Stream7, &DMA_InitStructure);
 
  /* Enable the USART Tx DMA request */
  USART_DMACmd(UART5, USART_DMAReq_Tx, ENABLE);
 
  /* Enable DMA Stream Transfer Complete interrupt */
  DMA_ITConfig(DMA1_Stream7, DMA_IT_TC, ENABLE);
 
  /* Enable the DMA RX Stream */
  DMA_Cmd(DMA1_Stream7, ENABLE);
}
 
/**************************************************************************************/
 
void DMA1_Stream7_IRQHandler(void)
{
  /* Test on DMA Stream Transfer Complete interrupt */
  if (DMA_GetITStatus(DMA1_Stream7, DMA_IT_TCIF7))
  {
    /* Clear DMA Stream Transfer Complete interrupt pending bit */
    DMA_ClearITPendingBit(DMA1_Stream7, DMA_IT_TCIF7);
  }
}
 
/**************************************************************************************/
 
void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
 
  /* Configure the Priority Group to 2 bits */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
 
  /* Enable the UART5 RX DMA Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = DMA1_Stream7_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}
 
/**************************************************************************************/
 
int main(void)
{
    RCC_Configuration();
 
  NVIC_Configuration();
 
    GPIO_Configuration();
 
  UART5_Configuration();
 
  DMA_Configuration();
 
  while(1); // Don't want to exit
}
 
/**************************************************************************************/
 
#ifdef  USE_FULL_ASSERT
 
/**
  * @brief  Reports the name of the source file and the source line number
  *   where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
 
  /* Infinite loop */
  while (1)
  {
  }
}
#endif
/**
  * @}
  */
 
/**************************************************************************************/