main.c

AVR单片机软件模拟串口实现全双工的例子。

/* 
	AVR Software-Uart Demo-Application 
	Version 0.3, 4/2007
	
	by Martin Thomas, Kaiserslautern, Germany
	<[e-mail]>
	http://www.siwawi.arubi.uni-kl.de/avr_projects
*/

/* 
Test environment/settings: 
- avr-gcc 4.1.1/avr-libc 1.4.5 (WinAVR 1/2007)
- Atmel ATtiny85 @ 1MHz internal R/C
- 2400bps

AVR Memory Usage (-Os)
----------------
Device: attiny85

Program:     874 bytes (10.7% Full)
(.text + .data + .bootloader)

Data:         52 bytes (10.2% Full)
(.data + .bss + .noinit)

*/

// #define WITH_STDIO_DEMO

#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include <avr/wdt.h> 
#include "softuart.h"
#include "gpio.h"

#ifdef WITH_STDIO_DEMO
#include <stdio.h>

// interface between avr-libc stdio and the modified Fleury uart-lib:
static int my_stdio_putchar( char c, FILE *stream )
{
	if ( c == '\n' ) {
		softuart_putchar( '\r' );
	}
	softuart_putchar( c );

	return 0;
}

FILE suart_stream = FDEV_SETUP_STREAM( my_stdio_putchar, NULL, _FDEV_SETUP_WRITE );

static void stdio_demo_func( void ) 
{
	stdout = &suart_stream;
	printf( "This output done with printf\n" );
	printf_P( PSTR("This output done with printf_P\n") );
}
#endif /* WITH_STDIO_DEMO */

unsigned char data_buf[8]={0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08};
//------------------------------------------------------------------------------
void delay_ms(unsigned int n)
{
	unsigned int zaehler;
	
	while (n) 
	{   
	    wdt_reset(); //喂狗	
		zaehler = F_CPU / 5000;
		while (zaehler) 
		{
			asm volatile ("nop");
			zaehler--;
		}
		n--;
	}
}
//------------------------------------------------------------------------------
int main(void)
{
	char c,i;
	static const char pstring[] PROGMEM = 
		"adapted for Atmel AVR and this demo by Martin Thomas\r\n";
	unsigned short cnt = 0;
#if (F_CPU > 4000000UL)
#define CNTHALLO (unsigned int)(0xFFFF)
#else 
#define CNTHALLO (unsigned int)(0xFFFF/3)
#endif
    gpio_init();
	softuart_init();
	wdt_enable(WDTO_1S); //看门狗使能1S(范围：15MS 30MS 60MS 120MS 250MS 500MS 1S 2S)
	softuart_turn_rx_on(); /* redundant - on by default */
	
	sei();
	
	softuart_puts_P( "\r\nSoftuart Demo-Application\r\n" );    // "implicit" PSTR
	softuart_puts_p( PSTR("generic softuart driver code by Colin Gittins\r\n") ); // explicit PSTR
	softuart_puts_p( pstring ); // pstring defined with PROGMEM
	softuart_puts( "--\r\n" );  // string "from RAM"

#ifdef WITH_STDIO_DEMO
	stdio_demo_func();
#endif
	
  while(1) 
	{
	
		if( softuart_kbhit()) 
		 {
		  for(i=0;i<8;i++)      //接收来自串口调试助手的8个字节
		   {
		    data_buf[i]=softuart_getchar();	
            wdt_reset(); //喂狗	  
		   }
		  //c = softuart_getchar();
		  //softuart_putchar( '[' );
		  //softuart_putchar( c );
		  //softuart_putchar( ']' );
		 }

		cnt++;
		if (cnt == CNTHALLO) 
		 {
		  cnt = 0;
		  wdt_reset(); //喂狗	
		  //softuart_puts_P( " Hello " );
		  softuart_puts(data_buf); //回发数据,通过调试助手可观察到
		  gpio_toggle_led(LED1);  //发光管取反
		  delay_ms(500);
		 }
		
	}
	
	return 0; /* never reached */
}