Stm32使用Usart代码例子（轮询、中断、DMA）

  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¤tviews=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 dogrn';  

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 %drn', file, line) */  

  /* Infinite loop */  

  while (1)  

  {  

  }  

}  

#endif  

/** 

  * @} 

  */  

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