【单片机】辉光管时钟系列<三>时钟芯片DS12C887

为了实现时钟显示，我们需要运用到时钟芯片。比较常用的时钟芯片为DS1302，在本文中我们采用更好的时钟芯片DS12C887。主要原因是DS1302需要案子后备电池和晶振，而DS12C887自带这两部分，在没有外部电源情况下可以工作10年。关于DS12C887的资料，可见链接：https://github.com/tengweitw/DS12C887

本文主要是通过STC89C52单片机与时钟芯片DS12C887通信，让LCD1602来显示时间，其电路原理图如下：

在图1中，关于单片机和1602液晶部分我们已经在前一篇文章《辉光管时钟系列<二>LCD液晶显示》中介绍过了。下面首先给出了时钟芯片DS12C887的实物图，如图2所示：

最后，我们可以根据DS12C887的datasheet来进行程序设计，简单的程序设计如下：

#include<reg52.h>
#define uchar unsigned char 
#define uint unsigned int

sbit lcdrs=P2^5;
sbit lcden=P2^7;

sbit dscs=P1^7;
sbit dsas=P1^6;
sbit dsrw=P1^5;
sbit dsds=P1^4;
uchar count,s1num;
char miao,shi,fen,day,date,month,year;

uchar code week[]=" 2021-05-17 MON";
uchar code time[]="    00:00:00";
uchar code weeks[]="SUNMONTUEWEDTHUFRISAT";
void delay(uint z)
{
	uint x,y;
	for(x=z;x>0;x--)
		for(y=110;y>0;y--);
}


//LCD Write command
void write_com(uchar com)
{
	lcdrs=0;
	lcden=0;
	P0=com;
	delay(5);
	lcden=1;
	delay(5);
	lcden=0;	
}

//LCD Write data
void write_date(uchar date)
{
	lcdrs=1;
	lcden=0;
	P0=date;
	delay(5);
	lcden=1;
	delay(5);
	lcden=0;	
}

// LCD Initialization
void lcdInit()
{

	write_com(0x38);
	write_com(0x0c);
	write_com(0x06);
	write_com(0x01);
}


//DS12C887 Write 
void write_ds(uchar add, uchar date)
{
	dscs=0;
	dsas=1;
	dsds=1;
	dsrw=1;
	P0=add;
	dsas=0;
	dsrw=0;
	P0=date;
	dsrw=1;
	dsas=1;
	dscs=1;
}

//DS12C887 Read
uchar read_ds(uchar add)
{
	uchar ds_date;
	dsas=1;
	dsds=1;
	dsrw=1;
	dscs=0;
	P0=add;
	dsas=0;
	dsds=0;
	P0=0xff;
	ds_date=P0;
	dsds=1;
	dsas=1;
	dscs=1;
	return ds_date;
}

//Write Time
void write_sfm(uchar add, uchar date)
{
	uchar shi, ge;
	shi=date/10;
	ge=date%10;
	write_com(0x80+0x40+add);
	write_date(0x30+shi);
	write_date(0x30+ge);
}

//Write Calendar
void write_calendar(uchar add, uchar shu)
{
	uchar shi,ge;
	shi=shu/10;
	ge=shu%10;
	write_com(0x80+add);
	write_date(0x30+shi);
	write_date(0x30+ge);
}

//Write week
void write_week(uchar date)
{
	write_com(0x80+12);
	write_date(weeks[3*date]);
	write_date(weeks[3*date+1]);
	write_date(weeks[3*date+2]);
}

void set_time()//设置日期和时间
{
//	write_ds(4,15);//时
//	write_ds(2,44);//分
//	write_ds(0,0);//秒
	write_ds(6,4);//星期
	write_ds(7,20);//日
	write_ds(8,5);//月
	write_ds(9,21);//年
}


void init()
{
	uchar num;
	set_time();//只在第一次初始化时钟芯片时用
	lcden=0;
//	fen=59;
//	miao=53;
//	shi=23;
	write_ds(0x0B,0x26);
	read_ds(0x0c);
	write_com(0x38);
	write_com(0x0c);
	write_com(0x06);
	write_com(0x01);
	write_com(0x80);
	for(num=0;num<15;num++)
		{
			write_date(week[num]);
			delay(5);
		}
	write_com(0x80+0x40);
	for(num=0;num<12;num++)
		{
			write_date(time[num]);
			delay(5);
		}

	miao=read_ds(0);
	fen=read_ds(2);
    shi=read_ds(4);
	day=read_ds(6);
	date=read_ds(7);
	month=read_ds(8);
	year=read_ds(9);
	write_sfm(10,miao);
	write_sfm(7,fen);
	write_sfm(4,shi);
	write_week(day);
    write_calendar(9,date);
	write_calendar(6,month);
	write_calendar(3,year);
}


void main()
{
	init();
	while(1)
	{
		miao=read_ds(0);
		fen=read_ds(2);
	    shi=read_ds(4);
		write_sfm(10,miao);
		write_sfm(7,fen);
		write_sfm(4,shi);
	}
}

效果图如下：