uart.c

《基于MDK的STM32处理器应用开发》例程,本例程包使用STM32 FirmLibrary V1.0

#include "config.h"

unsigned char Clock1s;
extern int  SendChar (int ch);         
void _ttywrch (int ch) { SendChar(ch); }
void _sys_exit (int return_code) { for (;;); }

int fputc (int ch, FILE *f) { return (SendChar(ch)); }
int ferror (FILE *f) {
  /* Your implementation of ferror */
  return EOF;
} 

GPIO_InitTypeDef  GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;

/*******************************************************************************
* Function Name  : SetupUART1
* Description    : Setup the UART1 
* Input          : None.
* Output         : None.
* Return         : None.
*******************************************************************************/
void SetupUART1 (void)  {

  GPIO_InitTypeDef  GPIO_InitStructure;
  USART_InitTypeDef USART_InitStructure;

  /* Enable GPIOA clock                                                       */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

  /* Configure USART1 Rx (PA10) as input floating                             */
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Configure USART1 Tx (PA9) as alternate function push-pull                */
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* USART1 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 Clock disabled
        - USART CPOL: Clock is active low
        - USART CPHA: Data is captured on the middle 
        - USART LastBit: The clock pulse of the last data bit is not output to 
                         the SCLK pin
  */
  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_InitStructure.USART_Clock               = USART_Clock_Disable;
  USART_InitStructure.USART_CPOL                = USART_CPOL_Low;
  USART_InitStructure.USART_CPHA                = USART_CPHA_2Edge;
  USART_InitStructure.USART_LastBit             = USART_LastBit_Disable;
  USART_Init(USART1, &USART_InitStructure);

  USART_Cmd(USART1, ENABLE); 
             /* Enable USART1                      */
   }


/* Implementation of putchar (also used by printf function to output data)    */
int SendChar (int ch)  {                /* Write character to Serial Port     */

  USART_SendData(USART1, (unsigned char) ch);
  while (!(USART1->SR & USART_FLAG_TXE));
  return (ch);
}