at17c256.c

AT17C256的I2C读写源程序

#include "2410addr.h"
#include "at17lv.h"

unsigned char wrbuf[PAGE_SIZE]; 
unsigned char rdbuf[PAGE_SIZE];
unsigned char databuf[32768];
unsigned char getbuf[32768];
unsigned int temp;

unsigned char SendByte(unsigned char byte, unsigned char order);
unsigned char GetByte(unsigned char lastbyte);

void WriteSCL(unsigned char state);
void WriteSDA(unsigned char state);

void WritePage(unsigned int address, unsigned char *bufptr); 
void ReadPage(unsigned int address, unsigned char *bufptr); 

void Init(void);
void Delay(void);
void Delaytime(void);

void SendStopBit(void);
void SendStartBit(void);

void Reset(void);


void C_Entry()
{ 
	unsigned int address,i, j = 0;
	unsigned int error=0;
    char *p = (char *)0x31000000;
    
    Init();
    
     for (i = 0; i < 32768; i++)
   		 databuf[i] =*(p+i);		
     
     
 	for(address=0,j=0;address<MAX_PAGES;address++)
    
      { 	 
      		        	 
      		for (i = 0; i < PAGE_SIZE; i++,j++)
   		     wrbuf[i] =databuf[j];
      		
      		WritePage(address,&wrbuf[0]); 
      	
      		Delaytime(); 
      	}


      	
      	for(address=0,j=0;address<MAX_PAGES;address++)
    
      { 	 
      		
      		ReadPage(address,&rdbuf[0]);
      		        	 
      		for (i = 0; i < PAGE_SIZE; i++,j++)
   		     getbuf[j]=rdbuf[i];
      		
      	
      		 
      	}
      	
      	for (i = 0,temp=0; i < 32768; i++)
      	   if(getbuf[i]!=databuf[i])
      	   {
      	   temp++;
      	   error=1;
      	   }
      	
      		
   	  Reset();          	            	 
		
        
         address=0x0;
         ReadPage(address,&rdbuf[0]);
            	     
   	     address=0xff;
         ReadPage(address,&rdbuf[0]);
               
         Reset();  	 
      	 	
         address=0xff;
         ReadPage(address,&rdbuf[0]);
         
         address=0x1ff;
         ReadPage(address,&rdbuf[0]);
         
         
         for(address=0;address<MAX_PAGES;address++)
         ReadPage(address,&rdbuf[0]);
         
         temp=0;
         while(1);
           	 
	
}
	


//100~400kHz


void Delay(void)
{
int i=0;
 while(i++<12)
 {};

return;

}


void Delaytime(void)
{
int i=0;
 while(i++<6000)
 {};

return;

}



void Init(void)
{

    /* GPE3  = SDA - bidirectional */
    /* GPE5  = SCL - output */
    /* GPE7  = SER_EN - output */
    /* GPE11 = CE - output */
    /* GPE4  = RESET/OE - output */
   rGPEUP=0x0ffff;
   rGPEDAT=0; 
}



void WritePage(unsigned int address, unsigned char *bufptr)
{
	unsigned char i; 
	unsigned char addr1; 
	unsigned char addr2; 
	
    rGPECON = 0x0fd7757ff;
    
//  	rGPEDAT=rGPEDAT&0x0f7ff; /* bring SER_EN low */	
//	rGPEDAT=rGPEDAT&0x0ff7f; /* bring RESET/OE low */
//	rGPEDAT=rGPEDAT&0x0fdff; /* bring CE low */
	
	Delay();
	
	Delay();
    
    addr1 = (unsigned char)(address >> 2);
    addr2 = (unsigned char)(address << 6);

    SendStartBit();

    SendByte(AT17 + WRITE,MSB_FIRST);	/* send device address byte with write bit */
    SendByte(addr1,MSB_FIRST);	          /* 1st address byte */
    SendByte(addr2,MSB_FIRST);	          /* 2nd address byte */

    for (i = 0; i < PAGE_SIZE; i++)
    SendByte(bufptr[i],LSB_FIRST);
        
    SendStopBit();
//    rGPEDAT=rGPEDAT|0x0800; /* bring SER_EN high */ 
//    rGPEDAT=rGPEDAT|0x80; /* bring RESET/OE high */
//    rGPEDAT=rGPEDAT|0x0200; /* bring CE high */
    
    
    Delay();
    rGPEDAT=0;
    Delay();
}


void ReadPage(unsigned int address, unsigned char *bufptr)
{
 	
	unsigned char i; 
	unsigned char addr1; 
	unsigned char addr2;	
	
	rGPECON = 0x0fd7757ff;
	
//	rGPEDAT=rGPEDAT&0x0f7ff; /* bring SER_EN low */
//	rGPEDAT=rGPEDAT&0x0ff7f; /* bring RESET/OE low */	
//	rGPEDAT=rGPEDAT&0x0fdff; /* bring CE low */
	Delay();	
    Delay();

    addr1 = (unsigned char)(address >> 2);
    addr2 = (unsigned char)(address << 6);

    SendStartBit();
    SendByte(AT17 + WRITE,MSB_FIRST);	/* send device address byte */

    SendByte(addr1,MSB_FIRST);	          /* 1st address byte */
    SendByte(addr2,MSB_FIRST);	          /* 2nd address byte */
	
	
    SendStartBit();
    SendByte(AT17 + READ,MSB_FIRST);  /* send device address byte with read bit */

	
	rGPEDAT=rGPEDAT&0x0efff;
    for (i = 0; i < (PAGE_SIZE-1); i++)
        bufptr[i] = GetByte(0);	
        
    bufptr[(PAGE_SIZE-1)] = GetByte(1); /* 1 signals last byte of read sequence */
	rGPEDAT=rGPEDAT|0x1000;
	
    SendStopBit();
    
//    rGPEDAT=rGPEDAT|0x0800; /* bring SER_EN high */   
 //   rGPEDAT=rGPEDAT|0x80; /* bring RESET/OE high */
//    rGPEDAT=rGPEDAT|0x0200; /* bring CE high */
    
    Delay();
    rGPEDAT=0;
    Delay();
}


unsigned char SendByte(unsigned char byte, unsigned char order)

{
unsigned char i;
unsigned char error;

    for (i = 0; i < 8; i++) 
{		Delay();
        if (order)

{
       WriteSDA(byte & 0x80);
       byte = byte << 1; 
       
        }
        else
{
      WriteSDA(byte & 0x01); 
      byte = byte >> 1; 
        }

        Delay();
        WriteSCL(1);
		Delay();
        Delay();
        WriteSCL(0);
        Delay();

    }
  
    rGPECON = 0x0fd7753ff;
    Delay();
    WriteSCL(1);
	Delay();
    /* SDA at 0 ?*/
    if(rGPEDAT&0x20==0)
    error = 0x1; /* ack didn't happen if bit 0 = 1 */
    else error =0x0;
	Delay();
	rGPECON = 0x0fd7757ff;
    WriteSCL(0);    
    Delay();
    return(error);
}




unsigned char GetByte(unsigned char lastbyte)
{
 
/* lastbyte == 1 for last byte */
unsigned char i, bit;
unsigned char result = 0;

    rGPECON = 0x0fd7753ff; /* SDA to input */
	//rGPEDAT=rGPEDAT&0x0ffdf;
    for (i = 0;i < 8;i++)
{
/* each bit at a time, LSB first */
	
		Delay();
        WriteSCL(1);
        Delay();
        if((rGPEDAT&0x20)==0)bit=0x0;
        else bit=0x1; 
		result = (bit << (i)) | result;  
        Delay();                          
        WriteSCL(0);
        Delay();
        
}
    /* send ACK */
    rGPECON = 0x0fd7757ff;  /* SDA to output */
    WriteSDA(0);    /* no ack on last byte ... lastbyte = 1 for the last byte */
    Delay();
    WriteSCL(1);
    Delay(); 
    Delay();
    WriteSCL(0);
    Delay();
	rGPECON = 0x0fd7753ff; /* SDA to input */  
    return(result);
}



void SendStartBit(void)

{	
	WriteSCL(0);
    WriteSDA(1);
    Delay();

    WriteSCL(1);
    Delay();
    WriteSDA(0);

    Delay();
    WriteSCL(0);
    Delay();

}

void SendStopBit(void)
{
	WriteSCL(0);
	WriteSDA(0);
    Delay();
    
    WriteSCL(1);
    Delay();
    WriteSDA(1);
    
    Delay();
    WriteSCL(0);
    Delay();

}






void WriteSCL(unsigned char state)
{
if (state)
		
        rGPEDAT=rGPEDAT|0x40; 
    else
		rGPEDAT=rGPEDAT&0x0ffbf;
         
}



void WriteSDA(unsigned char state)
{

if (state)
        rGPEDAT=rGPEDAT|0x20; 
    else
		rGPEDAT=rGPEDAT&0x0ffdf;
        
}

void Reset(void)
{
 	unsigned char result = 0;
	
    rGPECON = 0x0fd7757ff;
    
   

	rGPEDAT=rGPEDAT&0x0fdff;  /* bring CE low */

	rGPEDAT=rGPEDAT&0x0ff7f; /* bring RESET/OE low */
	Delay();
  
    rGPEDAT=rGPEDAT|0x0800; /* bring SER_EN high */
    Delay();
  
    SendStartBit();

    SendByte(AT17 + WRITE,MSB_FIRST);	/* send device address byte with write bit */
    
    SendByte(0x3f,MSB_FIRST);	          /* 1st address byte */
    SendByte(0xff,MSB_FIRST);	          /* 2nd address byte */
    
    SendByte(0xff,LSB_FIRST);
        
    SendStopBit();
    
    Delaytime();
    
    SendStartBit();

    SendByte(AT17 + READ,MSB_FIRST);  /* send device address byte with read bit */

    SendStopBit();
    result=GetByte(0);	
    
    rGPEDAT=rGPEDAT|0x0800; /* bring SER_EN high */ 
    Delay();
    rGPEDAT=rGPEDAT|0x0200; /* bring CE high */
	Delay();
	rGPEDAT=rGPEDAT|0x080;   /* bring RESET/OE high */
//	rGPEDAT=rGPEDAT&0xff7f; /* bring RESET/OE low */    


    Delay();
    rGPEDAT=0;
    Delay();
}