c - AVR GSM whit ATmega32 微控制器与 C# 应用程序的串行通信

Question

有人可以帮我为我的 AVR GSM 板编写一个简单的串行通信代码吗？我刚开始对微控制器进行编程，但我不确定我的代码是否正确，因为它可以构建，但是当我在板上烧录它时不起作用。我有一个可以连接到通信端口的 C# 应用程序，我想测试它的串行通信。板的型号是https://www.olimex.com/Products/AVR/Development/AVR-GSM/ 这是我的 MCU 代码：

#include <avr/io.h>
#include <stdio.h>
#include <stdbool.h>


#define BAUD 115200
#define MYUBRR F_CPU/16/BAUD-1

void usart_init(uint16_t ubrr);
char usart_getchar( void ); 
void usart_putchar( char data ); 
void usart_pstr(char *s);
unsigned char kbhit(void);

int main( void )
{
     // configure PORTA as output
       DDRA = 0xFF;
    // setup PORTB data direction as an input
    DDRB = 0;
    // make sure it is high impedance and will not source
    PORTB = 0;

    // fire up the usart
    usart_init ( MYUBRR );

    // dump some strings to the screen at power on
    usart_pstr("Welcome!\n\r");
    usart_pstr("Type in a character, and I will transpose it up by 1:\n\r");

    // main loop
    while(true) {
        // if a key has been pressed, then process it
        if(kbhit()) {
            usart_putchar(usart_getchar() + 1);
        }

        // map the PINB inputs to the PORTA outputs
        PORTA = PINB;

        // a little humor is always good, PB0 gets the user yelled at
        if(bit_is_clear(PINB,PB0)) {
            usart_pstr("OUCH! Stop poking me!\n\r");
        }
    }
    return 0;
}