高精度实时时钟－SD2001驱动程序 
/*------------------------------------------------------------------------------------------
[文件名] Sd.c
[功能] 对sd2001时钟进行时实读写，并对其内部的ram进行操作
[版本] 1.4b
[作者] 鞠春阳
[最后修改时间] 2003年5月12日
[版权所有] www.mcuzb.com
[sd2001资料] 请到www.mcuzb.com下载
===========================================================================================*/
//用户调用函数
//void initSD2001Time(unsigned char year,unsigned char month,unsigned char day,unsigned char date,unsigned char hour,unsigned char minute,unsigned char second)
//时钟初始化函数 年，月，日，星期，小时，分钟，秒
//ReadSD2001_Time() 
//读时间函数 结果分别存放在全局变量 SD2001_year SD2001_month ;SD2001_day ;SD2001_date ;SD2001_hour ;SD2001_minute;SD2001_second;中</P><P>
#include "reg51.h" 
#include "intrins.h" 
sbit SD2001_SDA= P2^1; 
sbit SD2001_SCL= P2^3; 
sbit SCLE = P1^5;
sbit SDAE = P1^4;#define SomeNOP(); { _nop_(); _nop_(); _nop_();_nop_(); }
unsigned char SD2001_year ;
unsigned char SD2001_month ;
unsigned char SD2001_day ;
unsigned char SD2001_date ;
unsigned char SD2001_hour ;
unsigned char SD2001_minute;
unsigned char SD2001_second;
unsigned char LishiSRAM[7];
/*--------------------------------------------------------------------------------
调用方式：void SD2001_I2CStart(void) ﹫2001/07/0 4
函数说明：私有函数，I2C专用
---------------------------------------------------------------------------------*/
void SD2001_I2CStart(void)
{
EA=0;
SD2001_SCL=0;
SD2001_SDA=1; SomeNOP();
SD2001_SCL=1; SomeNOP();//INI
SD2001_SDA=0; SomeNOP(); //START
SD2001_SCL=0;
}</P><P>void I2CStartRAM(void)
{
EA=0;
SCLE=0;
SDAE=1; SomeNOP();
SCLE=1; SomeNOP();//INI
SDAE=0; SomeNOP(); //START
SCLE=0;
}
/*--------------------------------------------------------------------------------
调用方式：void SD2001_I2CStop(void) ﹫2001/07/0 4
函数说明：私有函数，I2C专用
---------------------------------------------------------------------------------*/
void SD2001_I2CStop(void)
{
SD2001_SDA=0;
SD2001_SCL=0; SomeNOP(); //INI
SD2001_SCL=1; SomeNOP();
SD2001_SDA=1; SomeNOP();//STOP
SD2001_SCL=0;
EA=1;
}</P><P>void I2CStopRAM(void)
{
SDAE=0;
SCLE=0; SomeNOP(); //INI
SCLE=1; SomeNOP();
SDAE=1; SomeNOP();//STOP
SCLE=0;
EA=1;
}
/*--------------------------------------------------------------------------------
调用方式：void I2CSend(unsigned char ch) ﹫2001/07/0 5
函数说明：私有函数，I2C专用
MSB
---------------------------------------------------------------------------------*/
void SD2001_I2CSendByte(unsigned char ch)
{
unsigned char i=8;
while(i--)
{
SD2001_SCL=0;_nop_();
SD2001_SDA=(bit)(ch&0x80); ch<<=1; SomeNOP();
SD2001_SCL=1; SomeNOP();
}
SD2001_SCL=0;
// WaitAck();
}
/*--------------------------------------------------------------------------------
调用方式：void I2CSend(unsigned char ch) ﹫2001/07/0 5
函数说明：私有函数，I2C专用
LSB
---------------------------------------------------------------------------------*/
void SD2001_I2CSendByte1(unsigned char ch)
{
unsigned char i=8;
while(i--)
{
SD2001_SCL=0;_nop_();
SD2001_SDA=(bit)(ch & 0x01); ch>>=1; SomeNOP();
SD2001_SCL=1; SomeNOP();
}
SD2001_SCL=0;
//WaitAck();
}
//ACK
bitout()
{
SD2001_SDA=0;
SD2001_SCL=0;
SD2001_SDA=0;
SomeNOP();
SD2001_SCL=1; SomeNOP();
SD2001_SCL=0;
}
//接受时钟的1位
bit bitin()
{
bit temp;
SD2001_SDA=1;
SD2001_SCL=0;
SomeNOP();
temp=SD2001_SDA;
SomeNOP();
SD2001_SCL=1;
SomeNOP();
SD2001_SCL=0;
return(temp);
}
//接受时钟的1个字节
unsigned char rx()
{
unsigned char i=8;
unsigned char dat=0;
while(i--)
{
dat>>=1;
if(bitin())
dat=dat|0x80;
}
return(dat);
}
/*-------------SRAM-------------*/
SRAMACK()
{
SCLE=0; SomeNOP(); //ACK
SDAE=0; SomeNOP();
SCLE=1; SomeNOP();
SCLE=0; SomeNOP();
}
void SRAMSent(unsigned char ch) //发送一个字节给RAM
{
unsigned char i=8;
while(i--)
{
SCLE=0;_nop_();
SDAE=(bit)(ch&0x80); ch<<=1; SomeNOP();
SCLE=1; SomeNOP();
SCLE=0;
}
SDAE=1;
SCLE=0; SomeNOP(); //ACK
SCLE=1; SomeNOP(); //ACK
while(SDAE==1){} //ACK
SCLE=0;
}
SRAMRX() //接收一个字节从RAM
{
unsigned char i=8,dat=0;
SCLE=0;SomeNOP();
SDAE=1;SomeNOP();
while(i--)
{
SCLE=1;SomeNOP();
dat<<=1;
dat|=SDAE;
SCLE=0;
}
return(dat);
}
/*==============================*/
//改时钟
void initSD2001Time(unsigned char year,unsigned char month,unsigned char day,unsigned char date,unsigned char hour,unsigned char minute,unsigned char second)
{
SD2001_I2CStart();
SD2001_I2CSendByte(0x64); //从年开始写
bitout();</P><P> SD2001_I2CSendByte1(year); //写入年
bitout();
SD2001_I2CSendByte1(month);
bitout();
SD2001_I2CSendByte1(day);
bitout();
SD2001_I2CSendByte1(date);
bitout();
SD2001_I2CSendByte1(hour);
bitout();
SD2001_I2CSendByte1(minute);
bitout();
SD2001_I2CSendByte1(second);
bitout();
SD2001_I2CStop();
}</P><P>//读时间
ReadSD2001_Time()
{
unsigned char time[8]=0,i;
SD2001_I2CStart();
SD2001_I2CSendByte(0x65); //从年开始读
bitout();
i=8;
while(i--)
{
time[i]=rx();
bitout();
}
SD2001_I2CStop();
SD2001_year =time[7];
SD2001_month =time[6];
SD2001_day =time[5];
SD2001_date =time[4];
SD2001_hour =time[3]&0x7F;
SD2001_minute=time[2];
SD2001_second=time[1];
}
//时钟初始化
InitSD2001()
{
SD2001_I2CStart();
SD2001_I2CSendByte(0x62);//写状态寄存器
bitout();
SD2001_I2CSendByte1(0xC2);//Power 12/24 INT1AE INT2AE INT1ME INT2ME INT1FE INT2FE
// 1 1 0 0 0 0 1 0
SD2001_I2CStop();
}</P><P>//向ram写入数据
SaveToSRAM(unsigned int Address,unsigned char SRAM_Dat)
{
unsigned char AddrH,AddrL;
AddrL=Address;
AddrH=Address>>8;
I2CStartRAM();
SRAMSent(0xA0); //送关键字
SRAMSent(AddrH); //送高地址 已经含ACK
SRAMSent(AddrL); //送低地址
SRAMSent(SRAM_Dat);
I2CStopRAM();
}//从ram中读取数据
LoadFromSRAM(unsigned int Address)
{
unsigned char AddrH,AddrL,Dat;
AddrL=Address;
AddrH=Address>>8;
I2CStartRAM();
SRAMSent(0xA0); //送关键字 
SRAMSent(AddrH); //送高地址 已经含ACK 
SRAMSent(AddrL); //送低地址 
I2CStartRAM();
SRAMSent(0xA1);
Dat=SRAMRX();
I2CStopRAM();
return(Dat);
}
////////////////////////////////////////
main()
{
unsigned char a;
InitSD2001();
//initSD2001Time(0x03,0x01,0x20,0x01,0x15,0x50,0x00);//对表
ReadSD2001_Time();
SaveToSRAM(5,20);
a=LoadFromSRAM(5);</P><P>
while(1)
{
ReadSD2001_Time();
_nop_();
}
}