STM32F411RE-nucleo Printf 예제

#include <stdio.h>
#include "stm32f4xx.h"
 
int fputc(int ch, FILE *f)  {
    while(USART_GetFlagStatus(USART2, USART_FLAG_TXE)==0); /* TX가 가능할 때까지 blocking*/
    USART_SendData(USART2, ch); /* 데이터를 보낸다. */
    return (ch);
}
 
int main()
{
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    
    GPIO_InitTypeDef GPIO_InitStruct;
    
    GPIO_StructInit(&GPIO_InitStruct);
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_3;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_Init(GPIOA, &GPIO_InitStruct);
    
    GPIO_StructInit(&GPIO_InitStruct);
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_2;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOA, &GPIO_InitStruct);
    
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);
    
    USART_InitTypeDef USART_InitStructure;
    
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
    
    USART_StructInit(&USART_InitStructure);
    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(USART2, &USART_InitStructure);
    
    USART_Cmd(USART2, ENABLE);
 
    int16_t test_int = 0x1234;
    float   test_float = (float)test_int;
    
    printf("Int %x\r\n", test_int);
    printf("Float %f\r\n", test_float);
    
    while(1) {
        FlagStatus fStatus = USART_GetFlagStatus(USART2, USART_FLAG_RXNE); /* Recv 확인 */
        if(fStatus == SET ) { /* 있는 경우 */
            uint16_t rData = USART_ReceiveData(USART2); /* 데이터를 받는다 */
            printf("%c",(char) rData);
        }
    }
}