ds1307.h

一个基于51单片机的定时报警设计电路及程序

#include <reg52.h>
#include <intrins.h>

sbit SCL=P1^0;
sbit SDA=P1^1;

#define ACK 0
#define NACK 1
#define WRITE 0xd0
#define READ  0xd1
unsigned char Sec, Min, Hrs;
extern unsigned char led_buf[6];
unsigned char code zimo[16]={0xc0,0xf9,0xa4,0xb0,	// 0, 1, 2, 3
				0x99,0x92,0x82,0xf8,0x80,0x90};// 4, 5, 6, 7, 8, 9
void delayms(unsigned char ms)	
// 延时子程序
{
	unsigned char i;
	while(ms--)
	{
		for(i = 0; i < 120; i++);
	}
}
//I2C启始标志
void I2c_start(void)
{
	SDA = 1;
	SCL = 1;
	_nop_();
	_nop_();
	SDA = 0;
	_nop_();
	_nop_();
	SCL = 0;
	_nop_();
}
//I2C停止标志
void I2c_stop(void)
{
	SDA = 0;
	_nop_();
	_nop_();
	SCL = 1;
	_nop_();
	_nop_();
	_nop_();
	_nop_();
	SDA = 1;
	_nop_();
}

unsigned char I2c_read(unsigned char ack)
{
	unsigned char i,read_data;
	for(i = 0; i < 8; i++)
	{
		SCL = 1;
		_nop_();
		read_data <<= 1;
		read_data |= (unsigned char)SDA;
		SCL = 0;
		_nop_();
	}
	_nop_();
	SCL = 0;
	if(ack == NACK) SDA = 1; /* sda = 1 if next cycle is reset */
	else
		SDA=0;
	_nop_();
	SCL = 1;
	_nop_();
	SCL = 0;
	_nop_();
	SDA = 1;
	_nop_();
	return(read_data);
}

void I2c_write(unsigned char write_data)
{
	unsigned char i;
	bit ack_bit;
	for(i = 0; i < 8; i++)		// 循环移入8个位
	{
		SDA = (bit)(write_data & 0x80);
		SCL = 1;
		_nop_();
		_nop_();
		SCL = 0;
		_nop_();
		_nop_();
		write_data <<= 1;
	}
	SDA = 1;			// 读取应答
	_nop_();
	_nop_();
	SCL = 1;
	_nop_();
	_nop_();
	SCL = 0;
	_nop_();
	_nop_();
	ack_bit = SDA;
}

void Init_Rtc(unsigned char sec,unsigned char min,unsigned char hour)
{
	I2c_start(); 
	I2c_write(WRITE); 
	I2c_write(0x00); 
	I2c_write(sec); 
	I2c_write(min);
	I2c_write(hour);
	I2c_stop();
	delayms(10);
}

void WritetoRam(unsigned char add,unsigned char dat)
{
	I2c_start();
	I2c_write(WRITE);
	I2c_write(add);
	I2c_write(dat);
	I2c_stop();
}

void Read_time(void)
{
	I2c_start();
	I2c_write(WRITE); 
	I2c_write(0x00); 
	I2c_start();
	I2c_write(READ);
	Sec = I2c_read(ACK);
	Min = I2c_read(ACK);
	Hrs = I2c_read(NACK);
	I2c_stop();	
	delayms(10);	
}
void disp_time(void)
{
	unsigned char disp_temp[3];
	unsigned char temp_h,temp_l,i,j;
	Read_time();
	disp_temp[0]=Sec;
	disp_temp[1]=Min;
	disp_temp[2]=Hrs;
	do
	{
		temp_h=(disp_temp[j]&0xf0)>>4;
		temp_l=disp_temp[j]&0x0f;
		led_buf[i]=zimo[temp_l];
		i++;
		led_buf[i]=zimo[temp_h];
		i++;
		j++;
	}while(j<3);
	j=0;
	i=0;
}