DS1302-演示代码

参考DS1302数据手册，尽管数据手册是英文，但是很有帮助，再结合网上众多的代码写出了下面这个例子，除了涓流充电（trickle charger）功能没使用外，内部的RAM和寄存器功能都使用到了，包括多字节方式（burst mode）。自认为我写的比网上大多数程序清晰，当然已经硬件测试过了。

#include <reg52.h>

/*DS1302部分*/

//全部为写入地址，读取地址需要+1
#define YEAR 0x8c
#define MON 0x88
#define DATE 0x86
#define DAY 0x8a
#define HOUR 0x84
#define MIN 0x82
#define SEC 0x80
#define WP 0x8e
#define RAM(n) (0xc0+2*(n))
#define CLBT 0xbe
#define RAMBT 0xfe

//3个通信引脚
sbit SCLK=P2^1;
sbit IO=P2^0;
sbit RST=P2^4;    //有的使能端叫CE

unsigned char readbyte(void);
void writebyte(unsigned char dat);
void write1302(unsigned char addr,unsigned char dat);
unsigned char read1302(unsigned char addr);


/*数码管部分，6位共阴接在P0*/
sbit we=P2^7;
sbit du=P2^6;
void show(void);
void delayms(unsigned time);

unsigned char code table[] = {
0x3f , 0x06 , 0x5b , 0x4f,
0x66 , 0x6d , 0x7d , 0x07,
0x7f , 0x6f , 0x77 , 0x7c,
0x39 , 0x5e , 0x79 , 0x71,
0x00 };

unsigned char num[6]={0};    //用作数码管显示的数组

/*键盘部分，4个独立键盘接在P3.4-P3.7*/
void keyscan(void);
bit showdate=0;
bit showday=0;

void main(void)
{
    unsigned char temp;

    write1302(WP,0x00);    //允许写入，关闭写保护
    
    //clock burst 方式赋初值
    RST=0;
    SCLK=0;
    RST=1;
    writebyte(CLBT);

    writebyte(0x30);//秒分时
    writebyte(0x59);
    writebyte(0x23);

    writebyte(0x28);//日月
    writebyte(0x02);

    writebyte(0x02);//星期
    
    writebyte(0x32);//年

    writebyte(0x00);
    writebyte(0x00);
    RST=0;

//    另一种赋初值方法
//    write1302(HOUR,0x23);
//    write1302(MIN,0x59);
//    write1302(SEC,0x30);    

    while(1)
    {
        keyscan();
        if(showdate)
        {
            temp=read1302(YEAR+1);
            num[5]=temp>>4;
            num[4]=temp&0x0f;
            temp=read1302(MON+1);
            num[3]=temp>>4;
            num[2]=temp&0x0f;
            temp=showday?read1302(DAY+1):read1302(DATE+1);    
            num[1]=temp>>4;
            num[0]=temp&0x0f;
        }
        else
        {
            temp=read1302(HOUR+1);
            num[5]=temp>>4;
            num[4]=temp&0x0f;
            temp=read1302(MIN+1);
            num[3]=temp>>4;
            num[2]=temp&0x0f;
            temp=read1302(SEC+1);    
            num[1]=temp>>4;
            num[0]=temp&0x0f;
        }
        show();
    }

}


unsigned char readbyte(void)
{
    unsigned char i,ret;
    for(i=0;i<8;i++)
    {
        ret>>=1;
        SCLK=1;
        SCLK=0;
        ret|=IO?0x80:0x00;
    }
    return ret;
}

void writebyte(unsigned char dat)
{
    unsigned char i;
    for(i=0;i<8;i++)
    {
        IO=dat&1;
        SCLK=0;           
        SCLK=1;
        dat>>=1;
    }
}

void write1302(unsigned char addr,unsigned char dat)     
{
    RST=0;
    SCLK=0;
    RST=1;
    writebyte(addr);
    writebyte(dat);
    RST=0;         
}

unsigned char read1302(unsigned char addr)
{
    unsigned char ret;
    RST=0;
    SCLK=0;
    RST=1;
    writebyte(addr);
    ret=readbyte();
    RST=0;    
    return ret;
}

void show(void)
{
    unsigned char i;
    
    for(i=0;i<6;i++)
    {
        P0=0xff;
        we=1;
        we=0;      

        P0=table[num[i]];
        du=1;
        du=0;

        P0=~(0x20>>i);
        we=1;
        we=0;

        delayms(1);
    }
}

void delayms(unsigned time)
{
    unsigned i,j;

    for(i=time;i>0;i--)
        for(j=110;j>0;j--)
        ;
}

void keyscan(void)
{
    unsigned char temp;
    unsigned char reg[9];

    if((P3|0x0f)!=0xff)
    {
        delayms(10);
        if((temp=P3|0x0f)!=0xff)
        {
            while((P3|0x0f)!=0xff);
            switch(temp)
            {
            case 0xef:    //显示时间还是日期
                showdate=~showdate;
                break;
            case 0xdf:    //日期最后两位显示日还是星期
                showday=~showday;
                break;
            case 0xbf:    //将时钟寄存器保存到RAM
                RST=0;
                SCLK=0;
                RST=1;
                writebyte(CLBT+1);
                for(temp=0;temp<9;temp++)
                    reg[temp]=readbyte();
                RST=0;

                //从20号RAM开始存入，起始RAM号随意，只要不超过范围即可
                for(temp=0;temp<9;temp++)
                    write1302(RAM(20+temp),reg[temp]);

                /*    也可以用 RAM burst 写入
                RST=0;
                SCLK=0;
                RST=1;
                writebyte(RAMBT);
                for(temp=0;temp<9;temp++)
                    writebyte(reg[temp]);
                RST=0;
                */

                break;
            case 0x7f:    //从RAM恢复到时钟寄存器
                /*    对应的 RAM burst 读取
                RST=0;
                SCLK=0;
                RST=1;
                writebyte(RAMBT+1);
                for(temp=0;temp<9;temp++)
                    reg[temp]=readbyte();
                RST=0;
                */

                for(temp=0;temp<9;temp++)
                    reg[temp]=read1302(RAM(20+temp)+1);

                RST=0;
                SCLK=0;
                RST=1;
                writebyte(CLBT);
                for(temp=0;temp<9;temp++)
                    writebyte(reg[temp]);
                RST=0;
                break;
            }
        }
    }
}