STM32之UART

STM32的UART的驱动代码如下：

void BSP_Uart_SetBaud(uint32 u32Baud)
{
  GPIO_InitTypeDef s_GPIO_InitStructure;
  USART_InitTypeDef s_USART_InitStructure;
  NVIC_InitTypeDef s_NVIC_InitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);/*  使能GPIOA时钟*/
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);/*  使能USART1时钟*/
  USART_DeInit(USART2); 

  s_GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;            /*  PA9*/
  s_GPIO_InitStructure.e_GPIO_Speed = GPIO_Speed_50MHz;        
  s_GPIO_InitStructure.e_GPIO_Mode = GPIO_Mode_AF_PP;      /*  复用推挽*/
  GPIO_Init(GPIOA, &s_GPIO_InitStructure);

  s_GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;           /*  PA10*/
  s_GPIO_InitStructure.e_GPIO_Mode = GPIO_Mode_IN_FLOATING;/*  浮空输入*/
  GPIO_Init(GPIOA, &s_GPIO_InitStructure);  

  RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART2, ENABLE); /*  复位串口2*/
  RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART2, DISABLE);/*  停止复位*/

  s_USART_InitStructure.USART_BaudRate = u32Baud;        
  s_USART_InitStructure.USART_WordLength = USART_WordLength_8b;                    /*  8位数据长度*/
  s_USART_InitStructure.USART_StopBits = USART_StopBits_1;                         /*  一个停止位*/
  s_USART_InitStructure.USART_Parity = USART_Parity_No;                            /*  奇偶校验位*/
  s_USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;/*  无硬件数据流控制*/
  s_USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;                /*  收发模式*/

  USART_Init(USART2, &s_USART_InitStructure);     /*  初始化串口*/
  USART_ClearITPendingBit(USART2, USART_IT_RXNE);/*  清楚中断位*/
                                                    
  USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);/*  开启输入中断*/
                                                    
  USART_Cmd(USART2, ENABLE);                    /*  使能串口 */

  s_NVIC_InitStructure.NVIC_IRQChannel = (uint8)USART2_IRQn;   /*  使能串口2中断*/
  s_NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0U; /*  先占优先级2级*/
  s_NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1U;        /*  从优先级2级*/
  s_NVIC_InitStructure.e_NVIC_IRQChannelCmd = ENABLE;          /*  使能外部中断通道*/
  NVIC_Init(&s_NVIC_InitStructure); 
  
  /* 调试串口Uart1设置*/
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);/*  使能USART1时钟*/
  USART_DeInit(USART1); 

  s_GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;            /*  PA9*/
  s_GPIO_InitStructure.e_GPIO_Speed = GPIO_Speed_50MHz;        
  s_GPIO_InitStructure.e_GPIO_Mode = GPIO_Mode_AF_PP;      /*  复用推挽*/
  GPIO_Init(GPIOA, &s_GPIO_InitStructure);

  s_GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;           /*  PA10*/
  s_GPIO_InitStructure.e_GPIO_Mode = GPIO_Mode_IN_FLOATING;/*  浮空输入*/
  GPIO_Init(GPIOA, &s_GPIO_InitStructure);  

  RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, ENABLE); /*  复位串口2*/
  RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, DISABLE);/*  停止复位*/

  s_USART_InitStructure.USART_BaudRate = u32Baud;        
  s_USART_InitStructure.USART_WordLength = USART_WordLength_8b;                    /*  8位数据长度*/
  s_USART_InitStructure.USART_StopBits = USART_StopBits_1;                         /*  一个停止位*/
  s_USART_InitStructure.USART_Parity = USART_Parity_No;                            /*  奇偶校验位*/
  s_USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;/*  无硬件数据流控制*/
  s_USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;                /*  收发模式*/

  USART_Init(USART1, &s_USART_InitStructure);     /*  初始化串口*/                                                                                                
  USART_Cmd(USART1, ENABLE);                    /*  使能串口 */
}

使用的库函数如下:

/* 
***********************************************************
文 件 名: driver_usart.c
模    块: 片内外设usart的驱动模块
***********************************************************
*/
#include "driver_usart.h"
#include "driver_rcc.h"

#define CR1_UE_Set                ((uint16)0x2000)  /* !< USART Enable Mask */
#define CR1_UE_Reset              ((uint16)0xDFFF)  /* !< USART Disable Mask */
#define CR1_CLEAR_Mask            ((uint16)0xE9F3)  /* !< USART CR1 Mask */
#define CR2_STOP_CLEAR_Mask       ((uint16)0xCFFF)  /* !< USART CR2 STOP Bits Mask */
#define CR3_CLEAR_Mask            ((uint16)0xFCFF)  /* !< USART CR3 Mask */
#define IT_Mask                   ((uint16)0x001F)  /* !< USART Interrupt Mask */
#define CR1_OVER8_Set             ((uint16)0x8000)  /* USART OVER8 mode Enable Mask */

/* 
  * @brief  Deinitializes the USARTx peripheral registers to their default reset values.
  * @param  USARTx: Select the USART or the UART peripheral. 
  *   This parameter can be one of the following values: 
  *      USART1, USART2, USART3, UART4 or UART5.
  * @retval None
  */
void USART_DeInit(const USART_TypeDef* p_USARTx)
{
  if (p_USARTx == USART1)
  {
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, DISABLE);
  }
  else 
  {
    if (p_USARTx == USART2)
    {
      RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART2, ENABLE);
      RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART2, DISABLE);
    }
    else/*  其他*/
    {
      /*  nothing*/
    }
  }
}

/* 
  * @brief  Initializes the USARTx peripheral according to the specified
  *         parameters in the USART_InitStruct .
  * @param  USARTx: Select the USART or the UART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_InitStruct: pointer to a USART_InitTypeDef structure
  *         that c