eeprom1.c

主要介绍了24c16的读写,mcu为89s52,lcd为TC2002A,完成功能是把数据写入24c16中,再把数据从24c16读出,并显示在lcd中.编辑环境为keil2,已通过测试.

#include<reg52.h>
#include"port.h"
#include"main.h"
#include"eeprom.h"
#include<intrins.h>
bit SystemError;
uChar sendbuf[10];
uChar receivebuf[10];

void iic_start(void)
{

	SDA=1;
	SCL=1;

	SDA=0;

	SCL=0;
}
void iic_stop(void)
{

	SCL=1;
	SDA=0;
	SDA=1;
}

void slave_ACK(void)
{
	uChar i=0;
	SDA=1;
	do
	{
	  SCL = 0;
	  SCL = 1;
	}
	while((SDA) && (i++ < 100));//EepromScl=1:if EepromSda=0,exit
	SCL=0;
}

void slave_NOACK(void)
{
	SDA=1;
	SCL=1;
	SCL=0;
}

void check_ACK(void)
{
	SDA=1;
	SCL=1;
	F0=0;
	if(SDA==1)
		F0=1;
	SCL=0;
}

void IICSendByte(uChar ch)//发送一个byte 到eeprom
{
	uChar  n,j;
	 j=ch;
	for(n=0;n<8;n++)
	{
		if((j&0x80)==0x80)
			{
				SDA=1;
				
			 }
		else
			{
				SDA=0;
				
			 }
			 	SCL=1;
				SCL=0;
			 j=j<<1;
	 }
	 slave_ACK();//从机应答
}
uChar IICreceiveByte(void)
{
	uChar  n;
	uChar tdata;
	for(n=0;n<8;n++)
	{
		SDA=1;
		SCL=1;
		tdata=tdata<<1;
		if(SDA==1)
			tdata=tdata|0x01;
		else
			tdata=tdata&0xfe;
		 SCL=0;
	 }
	 SDA=0;
	 return(tdata);
}

void writeNByte(uInt slave_add,uChar n)//Write n Byte to eeprom  2006.8.3
{
	union u {uInt word; struct{uChar hi; uChar lo;}  bytes;};
	union u eepromAdd;
	uChar  send_da,i=0;
	eepromAdd.word=slave_add;                           //注意该处地址连续，对于24C16地址有效范围为0x0000 to 0x07ff 共2K
	eepromAdd.bytes.hi=(eepromAdd.bytes.hi&0x07)<<1;
	send_da=0;
	iic_start();
	IICSendByte(EEPROMWRCMD|eepromAdd.bytes.hi);
	IICSendByte(eepromAdd.bytes.lo);//write frist word address
	while(n--)
	{
		i+=3;
		send_da=i;
		IICSendByte(send_da);
		
	}
	iic_stop();
}

void receiveNByte(uChar  slave_add,uChar n)
{
	uChar  receive_da,i=0;
	iic_start();
	IICSendByte(slave_add);
	check_ACK();
	if(F0==1)
	{
		SystemError=1;
		return;
	}
	while(n--)
	{
		receive_da=IICreceiveByte();
		receivebuf[i++]=receive_da;
		slave_ACK();
	}
	slave_NOACK();
	iic_stop();
}
uChar EepromRead(uInt rdAddress)   //read a byte subprogram (8 bit)
{
	union u {uInt word; struct {uChar hi; uChar lo;} bytes;};
	union u eepromAdd;
	uChar rdData;
	eepromAdd.word=rdAddress;     //get address
	eepromAdd.bytes.hi=(eepromAdd.bytes.hi&0x07)<<1;//get the low three bits and shift move one bit
	iic_start();//produce start condition
	IICSendByte(EEPROMWRCMD|eepromAdd.bytes.hi);//write eeprom write command
	IICSendByte(eepromAdd.bytes.lo);//write frist word address
	
	iic_start();//produce start condition
	IICSendByte(EEPROMRDCMD|eepromAdd.bytes.hi);

	rdData=IICreceiveByte(); //read a byte from EEPROM
    slave_NOACK();
	
    iic_stop();
	
	return rdData;                 //return 
}

void EepromWrite(uInt wrAddress,uChar wrData)
{
	union u {uInt word; struct{uChar hi; uChar lo;}  bytes;};
	union u eepromAdd;
	uChar i = 0;
	eepromAdd.word=wrAddress;                           //注意该处地址连续，对于24C16地址有效范围为0x0000 to 0x07ff 共2K
	eepromAdd.bytes.hi=(eepromAdd.bytes.hi&0x07)<<1;  //将地址拆分，符合24系列的地址格式 
	if(wrData!=(EepromRead(wrAddress)))    //比较写入的内容与读出的内容是否一致
	{
		do
		{
		
            iic_start();       
			IICSendByte(EEPROMWRCMD|eepromAdd.bytes.hi); //产生报文，包含页地址，操作方式
		
			IICSendByte(eepromAdd.bytes.lo);
		
			IICSendByte(wrData);
          
            iic_stop();        
			EepromAckPolling(EEPROMWRCMD|eepromAdd.bytes.hi);                                              //轮询
		}	
		while((wrData!=(EepromRead(wrAddress))) && (i++ < 2));  //效验写入的值
	}       
}
void EepromAckPolling(uChar device)
{
	uChar i,j,k = 0;                            //define variable
	do
	{
		 iic_start();   //produce start condition
		j=device;
		for(i=0;i<8;i++)               //write 8 bit
			{
				if((j&0x80)==0)
				{
					SDA=0;		                //get the highest bit   
				}
				else
				{
					SDA=1;	
				}
				SCL=1;
				SCL=0;
				j=j<<1;         //move left wrTemp one bit 
			}
			SDA=1;
			SCL=1;
	}
	while((SDA) && (k++ < 100));	                         //EepromSda=0:exit
	SCL=0;
	SDA=0;
}