[Blue Bridge Road -- bug free code] DS1302 time module code analysis

initialization DS1302 The time of the module is 23:59：55, And read the time in real time

main.c

#include"STC15F2K60S2.h"
#include"ds1302.h"

typedef unsigned char uchar;
typedef unsigned int uint;

uchar dsp_code[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90};
uchar dsp_Time[8]={0xff,0xff,0xbf,0xff,0xff,0xbf};
uchar hour,min,sec;

void Timer0Init(void)		//1 millisecond @11.0592MHz
{
	AUXR |= 0x80;		// Timer clock 1T Pattern 
	TMOD &= 0xF0;		// Set timer mode 
	TL0 = 0xCD;		// Set initial value of timing 
	TH0 = 0xD4;		// Set initial value of timing 
	TF0 = 0;		// eliminate TF0 sign 
	TR0 = 1;		// Timer 0 Start timing 
	ET0=1;
	EA=1;
}

void serviceTimer() interrupt 1
{
	static uchar dsp_com=0;

	P0=0;P2=0xc0;P2=0;

	P0=dsp_Time[dsp_com];P2=0xe0;P2=0;

	P0=1<<dsp_com;P2=0xc0;P2=0;

	if(++dsp_com==8)dsp_com=0;
}

void Initsystem()
{
	P0=0xff;P2=0x80;P2=0;
	P0=0x00;P2=0xa0;P2=0;
}

void main()
{
	Initsystem();
	Set_Time(23,59,55);
	Timer0Init();
	while(1)
	{
		if(TH0<0xf0)
		{
			hour=Read_Ds1302_Byte(0x85);
			min=Read_Ds1302_Byte(0x83);
			sec=Read_Ds1302_Byte(0x81);

			dsp_Time[0]=dsp_code[hour/16];
			dsp_Time[1]=dsp_code[hour%16];
			dsp_Time[3]=dsp_code[min/16];
			dsp_Time[4]=dsp_code[min%16];
			dsp_Time[6]=dsp_code[sec/16];
			dsp_Time[7]=dsp_code[sec%16];
		}
	}
}

ds1302.c

/*
   Program description : DS1302 The driver 
   Software environment : Keil uVision 4.10 
   Hardware environment : CT107 SCM comprehensive training platform  8051,12MHz
   Japan      period : 2011-8-9
*/

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

sbit SCK=P1^7;		
sbit SDA=P2^3;		
sbit RST = P1^3;   // DS1302 Reset 												

void Write_Ds1302(unsigned  char temp) 
{
	unsigned char i;
	for (i=0;i<8;i++)     	
	{ 
		SCK=0;
		SDA=temp&0x01;
		temp>>=1; 
		SCK=1;
	}
}   

void  Write_Ds1302_Byte(unsigned char address,unsigned char dat )     
{
 	RST=0;
	_nop_();
 	SCK=0;
	_nop_();
 	RST=1;	
   	_nop_();  
 	Write_Ds1302(address);	
 	Write_Ds1302(dat);		
 	RST=0; 
}

unsigned char Read_Ds1302_Byte ( unsigned char address )
{
 	unsigned char i,temp=0x00;
 	RST=0;
	_nop_();
 	SCK=0;
	_nop_();
 	RST=1;
	_nop_();
 	Write_Ds1302(address);
 	for (i=0;i<8;i++) 	
 	{		
		SCK=0;
		temp>>=1;	
 		if(SDA)
 		temp|=0x80;	
 		SCK=1;
	} 
 	RST=0;
	_nop_();
 	RST=0;
	SCK=0;
	_nop_();
	SCK=1;
	_nop_();
	SDA=0;
	_nop_();
	SDA=1;
	_nop_();
	return (temp);			
}

void Set_Time(char hour,char min,char sec)
{
	Write_Ds1302_Byte(0x8e,0x00);
	Write_Ds1302_Byte(0x84,(hour/10)*16+hour%10);
	Write_Ds1302_Byte(0x82,(min/10)*16+min%10);
	Write_Ds1302_Byte(0x80,(sec/10)*16+sec%10);
	Write_Ds1302_Byte(0x8e,0x80);
}		

ds1302.h

#ifndef __DS1302_H
#define __DS1302_H

void Write_Ds1302_Byte(unsigned  char temp);
void Write_Ds1302( unsigned char address,unsigned char dat );
unsigned char Read_Ds1302_Byte ( unsigned char address );
void Set_Time(char hour,char min,char sec);

#endif