STM32L152RC 在keil4中使用printf()和scanf() 函數

STM32L152RC 在keil4中使用printf()和scanf() 函數

1、在keil中配置使用Micro LIB，如下圖

2、配置USART模塊

 void SYS_USARTInit(void)
{
    static USART_InitTypeDef USART_InitStructure;
    static GPIO_InitTypeDef GPIO_InitStructure;

    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;


    /* Enable GPIO clock */
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE); 
    /* Enable UART clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
    /* Connect PA9 to USARTx_Tx */
    GPIO_PinAFConfig(USE_USART_PORT, USE_USART_TX_GPIO_PinSource, GPIO_AF_USART1);

    /* Connect PA10 to USARTx_Rx */
    GPIO_PinAFConfig(USE_USART_PORT, USE_USART_RX_GPIO_PinSource, GPIO_AF_USART1);

    /* Configure USART Tx PA9 as alternate function push-pull */
    GPIO_InitStructure.GPIO_Pin = USE_USART_TX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(USE_USART_PORT, &GPIO_InitStructure);

    /* Configure USART Rx PA10 as alternate function push-pull */
    GPIO_InitStructure.GPIO_Pin = USE_USART_RX_PIN;
    GPIO_Init(USE_USART_PORT, &GPIO_InitStructure);

    /* USART configuration */
    USART_Init(USE_USART, &USART_InitStructure);

    /* Enable USART */
    USART_Cmd(USE_USART, ENABLE);
}

3、重定向printf()

在工程中加入下面代碼

#ifdef __GNUC__
  /* With GCC/RAISONANCE, small printf (option LD Linker->Libraries->Small printf
     set to 'Yes') calls __io_putchar() */
  #define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#else
  #define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
  #define GETCHAR_PROTOTYPE int fgetc(FILE *f)
#endif /* __GNUC__ */
PUTCHAR_PROTOTYPE
{
    /* Place your implementation of fputc here */
    /* e.g. write a character to the USART */
    USART_SendData(USE_USART, (uint8_t)ch);
    /* Loop until transmit data register is empty */
    while (USART_GetFlagStatus(USE_USART, USART_FLAG_TXE) == RESET)
    {}
    return ch;
}
GETCHAR_PROTOTYPE
{
    while(USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == RESET);
    return (USART_ReceiveData(USART1));
}

上面三個步驟做完即可在工程中調用printf()和scanf()了。