main.c

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/*
 * DS1302 突发方式，连读，连写
 *
*/

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

typedef unsigned char uint8;
typedef unsigned int uint16;

sbit SCK = P3^5;	//时钟	
sbit SDA = P3^4;	//数据	
sbit RST = P1^7;    //DS1302复位(片选)

#define DS1302_W_ADDR 0xBE
#define DS1302_R_ADDR 0xBF


uint8 time[7]={50,59,23,15,8,7,10};//秒分时日月周年10-08-15 23:59:50


void delay(uint16 n)
{
	while (n--);
}

/**
 * 写一个字节
*/
void write_ds1302_byte(uint8 dat) 
{
	uint8 i;
	
	for (i=0;i<8;i++) 
	{ 
		SDA = dat & 0x01;
		SCK = 1;
		dat >>= 1;
		SCK = 0;
	}
}

/**
 * 读一个字节
*/
uint8 read_ds1302_byte(void) 
{
	uint8 i, dat=0;
	
	for (i=0;i<8;i++)
	{	
		dat >>= 1;
		if (SDA)
			dat |= 0x80;
		SCK = 1;
		SCK = 0;
	} 

	return dat;
}

void reset_ds1302(void)
{
	RST = 0;
	SCK = 0;
	RST = 1;
}

/**
 * 清除写保护
*/
void clear_ds1302_WP(void) 
{
	reset_ds1302();
	RST = 1;
	write_ds1302_byte(0x8E);
	write_ds1302_byte(0);
	SDA = 0;
	RST = 0;
}

/**
 * 设置写保护
*/
void set_ds1302_WP(void) 
{
	reset_ds1302();
	RST = 1;
	write_ds1302_byte(0x8E);
	write_ds1302_byte(0x80);
	SDA = 0;
	RST = 0;
}


/**
 * 设定时钟数据
*/
void set_time(uint8 *timedata)
{
	uint8 i, tmp;

	for (i=0; i<7; i++)  // 转化为BCD格式
	{
		tmp = timedata[i] / 10;
		timedata[i] = timedata[i] % 10;
		timedata[i] = timedata[i] + tmp*16;
	}

	clear_ds1302_WP();

	reset_ds1302();
	RST = 1;
	write_ds1302_byte(DS1302_W_ADDR);
	for (i=0; i<7; i++)
	{
		write_ds1302_byte(timedata[i]);
		delay(10);
	}
	write_ds1302_byte(0);
	SDA = 0;
	RST = 0;

	set_ds1302_WP();
}

/**
 * 读时钟数据（BCD格式）
*/
void read_time(uint8 *timedata)
{
	uint8 i;

	clear_ds1302_WP();

	reset_ds1302();
	RST = 1;
	write_ds1302_byte(DS1302_R_ADDR);
	for (i=0; i<7; i++)
	{
		timedata[i] = read_ds1302_byte();
		delay(10);
	}
	SDA = 0;
	RST = 0;

	set_ds1302_WP();
}



/**
 * UART初始化
 * 波特率：9600
*/
void uart_init(void)
{
    TMOD = 0x21;        // 定时器1工作在方式2（自动重装）
    SCON = 0x50;        // 10位uart，允许串行接受

    TH1 = 0xFD;
    TL1 = 0xFD;

    TR1 = 1;
}

/**
 * UART发送一字节
*/
void UART_Send_Byte(uint8 dat)
{
	SBUF = dat;
	while (TI == 0);
	TI = 0;
}

/**
 * 将数据转换成ASC码并通过UART发送出去
*/
void UART_Send_Dat(uint8 dat)
{
	UART_Send_Byte(dat/16 + '0');
	UART_Send_Byte(dat%16 + '0');
}

main()    
{

	uart_init();
 	set_time(&time);    //设定时间值

	while(1)
	{

		read_time(&time);   //秒分时日月周年
  	
		UART_Send_Dat(time[6]);
		UART_Send_Byte('-');
		UART_Send_Dat(time[4]);
		UART_Send_Byte('-');
		UART_Send_Dat(time[3]);
		UART_Send_Byte(' ');

		UART_Send_Dat(time[2]);
		UART_Send_Byte(':');
		UART_Send_Dat(time[1]);
		UART_Send_Byte(':');
		UART_Send_Dat(time[0]);
		UART_Send_Byte('\r');
		UART_Send_Byte('\n');

		delay(10000);
	}
}