timer0.c

AVR 单片机 时钟显示 通过7279 用数码管

//ICC-AVR application builder : 2007-12-14 下午 03:35:52
// Target : M16
// Crystal: 8.0000Mhz

#include <iom16v.h>
#include <macros.h>
#include<slavr.h>
unsigned char hour=0;
unsigned char minute=0;
unsigned char second=0;
unsigned char counter=0;
//*******************发送字节*******************
void send_byte( unsigned char out_byte)
{
	unsigned char i;
	for (i=0;i<8;i++)
	{
		if (out_byte&0x80)
		{
			PORTB|=BIT(PB1); //置1data
		}
		else
		{					 		   			 
			PORTB&=~BIT(PB1);//清零
		}
		PORTB|=BIT(PB2);//置1
		out_byte<<=1;
		delay_us(30);//20//32//30
		PORTB&=~BIT(PB2); //清零
		delay_us(30);//32//30
	}
	PORTB&=~BIT(PB1);//清零
	//delay_us(50); 
	//PORTB|=BIT(PB3);//清零cs1	

}
//*******************写入7279*******************


//**********************************************
void write7279(unsigned char cmd, char dta ) //写入7279
{
	CLI();
	delay_us(62);//50//55//62
	send_byte (cmd);
	delay_us(33);//20//28//33
	send_byte (dta);
	SEI();
} 
void display(void)
{
write7279(0x83,second%10);//
write7279(0x82,second/10);
write7279(0x81,minute%10);
write7279(0x80,minute/10);
write7279(0x85,hour%10);
write7279(0x84,hour/10);
}
void port_init(void)
{
 PORTA = 0x00;
 DDRA  = 0x00;
 PORTB = 0x06;
 DDRB  = 0x0E;
 PORTC = 0x00; //m103 output only
 DDRC  = 0x00;
 PORTD = 0x00;
 DDRD  = 0x00;
}

//TIMER0 initialize - prescale:1024
// WGM: Normal
// desired value: 10mSec
// actual value:  9.984mSec (0.2%)
void timer0_init(void)
{
 TCCR0 = 0x00; //stop
 TCNT0 = 0xB2; //set count
 OCR0  = 0x4E;  //set compare
 TCCR0 = 0x05; //start timer
}

#pragma interrupt_handler timer0_ovf_isr:10
void timer0_ovf_isr(void)
{
 TCNT0 = 0xB2; //reload counter value
 if (counter<10) counter++;
 else {counter=0 ;    
       if (second<60) second++;
       else {second=0 ;
	         if (minute<60) minute++;
			 else {minute=0;
			       if (hour<24) hour++;
				   else hour=0;
				   }
		    }
		}
}

//call this routine to initialize all peripherals
void init_devices(void)
{
 //stop errant interrupts until set up
 CLI(); //disable all interrupts
 port_init();
 timer0_init();

 MCUCR = 0x00;
 GICR  = 0x00;
 TIMSK = 0x01; //timer interrupt sources
 SEI(); //re-enable interrupts
 //all peripherals are now initialized
}
void main(void)
{
init_devices();
for(;;)
display();
}