usart

/**
 *  Keil project template
 *
 *  Before you start, select your target, on the right of the "Load" button
 *
 *  @author     Tilen Majerle
 *  @email      tilen@majerle.eu
 *  @website    http://stm32f4-discovery.com
 *  @ide        Keil uVision 5
 *  @conf       PLL parameters are set in "Options for Target" -> "C/C++" -> "Defines"
 *  @packs      STM32F4xx Keil packs version 2.4.0 or greater required
 *  @stdperiph  STM32F4xx Standard peripheral drivers version 1.5.0 or greater required
 */
/* Include core modules */
#include "stm32f4xx.h"
/* Include my libraries here */
#include "defines.h"
#include "tm_stm32f4_delay.h"
#include "tm_stm32f4_disco.h"
#include "tm_stm32f4_usart.h"
#include "tm_stm32f4_stdio.h"

int main(void) {

    /* Initialize system */
    SystemInit();

    /* Initialize delay */
    TM_DELAY_Init();

    TM_USART_Init(USART2, TM_USART_PinsPack_1, 9600);

    while (1) {
        int a,b;
        a=b=10;
        printf("a=");
        scanf("%d", &a);
        printf("b=");
        scanf("%d", &b);
        printf("a*b=%d", a*b);
        Delayms(1000);
    }
}

/* Handle stdout actions */
int TM_STDIO_StdoutHandler(int ch, FILE* f) {
    /* Send data to USART1 */
    TM_USART_Putc(USART2, (char) ch);

    /* Return ch, it means OK */
    return ch;
    /* If you want to return error, then you have to send EOF (-1) */
    //return -1;
}

/* Handle stdin actions */
int TM_STDIO_StdinHandler(FILE* f) {
    /* If any data at USART, return them */
    /* Do your custom implementation here when string ends */
    if (!TM_USART_BufferEmpty(USART2)) {
        return (int)TM_USART_Getc(USART2);
    }
    /* End of data, string is valid */
    /* You have to send -1 at the end of string */
    return -1;
}