复件 master.c

avr单片机的一些实际应用源码

/*
	master :
	main.c
	
	芯艺 2004-09-02   ---------- 2004
*/


#include <avr/io.h>
#include <avr/delay.h>

#include <avr/twi.h>

#define uint unsigned int
#define uchar unsigned char

#define SET_RED_LED cbi(PORTB,1)
#define CLR_RED_LED sbi(PORTB,1)

#define SET_GRN_LED cbi(PORTB,2)
#define CLR_GRN_LED sbi(PORTB,2)

#define SET_YEL_LED cbi(PORTB,0)
#define CLR_YEL_LED sbi(PORTB,0)

#define LEFT_KEY	0X08
#define RIGHT_KEY	0X04

#define FREQ 4
#define TWI_ADDRESS 0X32

void DelayMs(uint ms)
{
	uint i;
	for(i=0;i<ms;i++)
		_delay_loop_2(FREQ *250);
}

/*************主模式TWI操作部分*************开始**************/

//总线上起动停止条件
void twi_stop(void)
{
	TWCR = _BV(TWINT) | _BV(TWSTO) | _BV(TWEN);
}
//总线上起动开始条件
void twi_start(void)
{
	uchar trycount=0;

	TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN); 
	while ((TWCR & _BV(TWINT)) == 0) ;

	SET_GRN_LED;
	
	return TW_STATUS;
}

//写一字节
void twi_writebyte(uchar c)
{
	TWDR = c;
	TWCR = _BV(TWINT) | _BV(TWEN); 	
	while ((TWCR & _BV(TWINT)) == 0);
	return TW_STATUS;
}

//读一字节 ack: true时发ACK，false时发NACK
uchar twi_readbyte(uchar *c ,uchar ack)
{
	uchar tmp=_BV(TWINT)|_BV(TWEN);
		
	if(ack)
		tmp|=_BV(TWEA); 	
	TWCR=tmp;
	while ((TWCR & _BV(TWINT)) == 0) ;

	*c=TWDR;

	return TW_STATUS;
}
/*************主模式IIC操作部分*************结束**************/

uchar WaitKeyDown(void)
{
	uchar key;
	
	while(1)
	{
		key=PIND & 0x0c;
		if(	key!=0x0c)
		{
			DelayMs(30);
			key=PIND & 0x0c;
			if(key!=0x0c)
				break;
		}
		DelayMs(1);
	}
	if(key & LEFT_KEY)
		SET_YEL_LED;
	else if(key & RIGHT_KEY)
		SET_RED_LED;
	while((PIND & 0X0C)!=0X0C)
		DelayMs(10);
		
	CLR_RED_LED;
	CLR_YEL_LED;
	
	return key;
}

int main(void)
{
	uchar i,j;
	
	DDRB=0XFF;
	PORTB=0XFF;
	
	DDRC=0;
	PORTC=0X30;
	
	DDRD=0;
	PORTD=0;
	
	TWBR=73;
	
	SET_GRN_LED;
	
	while(1)
	{
		i=WaitKeyDown();
		
		if( i== LEFT_KEY )
		{
			twi_start();
			DelayMs(100);
			twi_writebyte(TWI_ADDRESS|TW_WRITE);
			DelayMs(100);
			for(j=0;j<10;j++)
			{
				twi_writebyte(j);
				DelayMs(100);
			}
			twi_stop();
		}
		else if(i==RIGHT_KEY)
		{	
				
		}
	}
}