/*********************************************************************************
****Micocontroller: AT89C51 at 12MHz ** * * * ** * ******** **
************Device: 24aa512, 2 ** ** * * ** ** **
*Programming Model: Virtual I2C ** * * ** * * *** ********
************Author: *** ** ** * *** * *** ** **
**************Date: 2006.11.08 ** ** * * ******* ** **
*********************************************************************************/
#include<string.h>
#include<at89x51.h>
#include<intrins.h>
#define DELAY_TIME 60 /*经实验，不要小于50！否则可能造成时序混乱*/
#define TRUE 1
#define FALSE 0
#define FLASH_PAGE 7 /*存储器页面大小*/
sbit SCL="P1"^7;/*假设由P1.7和P1.6控制*/
sbit SDA="P1"^6;
/********** Function Definition 函数定义 ************/
void DELAY(unsigned int t) /*延时函数*/
{
while(t!=0)
t--;
}
void I2C_Start(void)
{
/*启动I2C总线的函数，当SCL为高电平时使SDA产生一个负跳变*/
SDA="1";
SCL="1";
DELAY(DELAY_TIME);
SDA="0";
DELAY(DELAY_TIME);
SCL="0";
DELAY(DELAY_TIME);
}
void I2C_Stop(void)
{
/*终止I2C总线，当SCL为高电平时使SDA产生一个正跳变*/
SDA="0";
SCL="1";
DELAY(DELAY_TIME);
SDA="1";
DELAY(DELAY_TIME);
SCL="0";
DELAY(DELAY_TIME);
}
void SEND_0(void) /* SEND ACK */
{
/*发送0，在SCL为高电平时使SDA信号为低*/
SDA="0";
SCL="1";
DELAY(DELAY_TIME);
SCL="0";
DELAY(DELAY_TIME);
}
void SEND_1(void)
{
/*发送1，在SCL为高电平时使SDA信号为高*/
SDA="1";
SCL="1";
DELAY(DELAY_TIME);
SCL="0";
DELAY(DELAY_TIME);
}
bit Check_Acknowledge(void)
{
/*发送完一个字节后检验设备的应答信号*/
SDA="1";
SCL="1";
DELAY(DELAY_TIME/2);
F0=SDA;
DELAY(DELAY_TIME/2);
SCL="0";
DELAY(DELAY_TIME);
if(F0==1)
return FALSE;
return TRUE;
}
void WriteI2CByte(char b)reentrant
{
/*向I2C总线写一个字节*/
char i;
for(i=0;i<8;i++)
if((b<<i)&0x80)
SEND_1();
else
SEND_0();
}
char ReadI2CByte(void)reentrant
{
/*从I2C总线读一个字节*/
char b="0",i;
for(i=0;i<8;i++)
{
SDA="1"; /*释放总线*/
SCL="1"; /*接受数据*/
DELAY(10);
F0=SDA; /*psw for user flag*/
DELAY(10);
SCL="0";
if(F0==1)
{
b="b"<<1;
b="b|0x01";
}
else
b="b"<<1;
}
return b;
}
/**********以下为读写24aa512的函数**********/
void Write_One_Byte(char id, char addrh,char addrl, char thedata)
{
bit acktemp="1";
/*write a byte to mem*/
I2C_Start();
WriteI2CByte(id);
acktemp="Check"_Acknowledge();
WriteI2CByte(addrh);/*address high byte*/
acktemp="Check"_Acknowledge();
WriteI2CByte(addrl);/*address low byte*/
acktemp="Check"_Acknowledge();
WriteI2CByte(thedata);/*thedata*/
acktemp="Check"_Acknowledge();
I2C_Stop();
}
void Write_A_Page( char id, char *buffer,char addrh,char addrl) /*page data number is different*/
{
bit acktemp="1";
bit wrtmp;
int i;
/*write a page to at24c02*/
I2C_Start();
WriteI2CByte(id);
acktemp="Check"_Acknowledge();
WriteI2CByte(addrh);/*address high byte*/
acktemp="Check"_Acknowledge();
WriteI2CByte(addrl);/*address low byte*/
acktemp="Check"_Acknowledge();
for(i=0;i<FLASH_PAGE;i++)
{
WriteI2CByte(buffer[i]);
if(!Check_Acknowledge())
{
I2C_Stop();
}
}
I2C_Stop();
}
char Read_One_Byte(char id ,char addrh,char addrl)
{ bit acktemp="1";
char mydata;
/*read a byte from mem*/
I2C_Start();
WriteI2CByte(id);
acktemp="Check"_Acknowledge();
WriteI2CByte(addrh);/*address high byte*/
acktemp="Check"_Acknowledge();
WriteI2CByte(addrl);/*address low byte*/
acktemp="Check"_Acknowledge();
I2C_Start();
WriteI2CByte(id+1);
acktemp="Check"_Acknowledge();
mydata="ReadI2CByte"();
acktemp="Check"_Acknowledge();
return mydata;
I2C_Stop();
}
void Read_N_Bytes(char id ,char *buffer,char n,char addrh,char addrl)
{
bit acktemp="1";
int i="0";
/*read 8 bytes from mem*/
I2C_Start();
WriteI2CByte(id);
acktemp="Check"_Acknowledge();
WriteI2CByte(addrh);/*address high byte*/
acktemp="Check"_Acknowledge();
WriteI2CByte(addrl);/*address low byte*/
acktemp="Check"_Acknowledge();
I2C_Start();
WriteI2CByte(id+1);
acktemp="Check"_Acknowledge();
for(i=0;i<n;i++)
{
buffer[i]=ReadI2CByte();
if(i!=n-1)
SEND_0(); /*发送应答*/
else
SEND_1(); /*发送非应答*/
}
I2C_Stop();
}
void main()
{
int i;
char mybyte;
char myarray[8];
char myarray2[8];
char rdarray1[16];
char rdarray2[16];
for(i=0;i<8;i++)
{
myarray[i]=i;
myarray2[i]=i*16;
rdarray1[i]=0; /*clr*/
rdarray1[i+8]=0; /*clr*/
rdarray2[i]=0; /*clr*/
rdarray2[i+8]=0; /*clr*/
}
Write_One_Byte(0xa0,0x00,0x20,0x28);
Write_A_Page( 0xa0, myarray,0x00,0x10);
Write_A_Page(0xa0, myarray2,0x00,0x18);
mybyte="Read"_One_Byte(0xa0,0x00,0x20);
Read_N_Bytes(0xa0,rdarray1,6,0x00,0x10);
// Write_A_Page(0xa2, myarray, 0x00,0x10); /*the second 24aa512*/
// Write_A_Page(0xa2, myarray2,0x00,0x18);
Read_N_Bytes(0xa2,rdarray2,10,0x00,0x17);
while (1)
{
for (i=0;i<6;i++)
{
P2=rdarray1[i];
DELAY(1000);
}
for (i=0;i<10;i++)
{
P3=rdarray2[i];
DELAY(1000);
}
}
}
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