stm32使用庫函數(shù)編寫USART還是很方便的，現(xiàn)在轉幾個例子：

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

轉載請注明出處：tedeum.iteye.com 

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

 首先是不使用中斷的方法使用usart1,管腳pa9,pa10，此方法已在f3discovery上驗證通過，來源：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¤tviews=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 %drn', file, line) */  

  /* Infinite loop */  

  while (1)  

  {  

  }  

}  

#endif  

接下來是使用中斷的方法，使用USART3，管腳pd8，pd9，來源：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¤tviews=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 dogrn';  

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

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;