2018年09月08日 | STM32L152RC 在keil4中使用printf()和scanf() 函数

1、在keil中配置使用Micro LIB，如下图

2、配置USART模块

 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码

#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));

}

上面三个步骤做完即可在工程中调用printf()和scanf()了。