EEPW论坛

给你一个源码看看！

/********************************************************************/

void i2c_init(void)
{
 PACNT_init;
 PADDR_init;
 PADAT_init;
 
 SCL_high;
 SDA_high;
}
 
/********************************************************************/

uint8 i2c_write(uint8 slave_address, uint8 *buffer, int byte_count, int freq)
{
    uint8 out_mask = 0x80;
    uint8 value = 0x00;
  uint8 send_byte = 0x00;
  uint8 status = 0x81;
  int count = 8;
  int clk_count = 0;
 int i = 0;
 
 /* Set delay value based on frequency. */
 int D = (int) ((4000/freq) - 14);
 
 slave_address = (slave_address & 0xFE);
         
  i2c_start();
  delay(500);
 
   send_byte = slave_address;
        
   for(i = 0; i <= byte_count; i++)
   {    
    count = 8; 
    out_mask = 0x80;
         
    /* Send data bytes one bit at a time. */   
    while(count > 0)
    {            
     value = ((send_byte & out_mask) ? 1 : 0);
      if (value == 1)
      {
       PADAT_init;
        SDA_high;}
      else
      {
       PADAT_init;
       SDA_low;}
       
      delay(D);     
                   
        PADAT_init;
      SCL_high;
      
      /* Clock stretching wait statement.  Wait until clock is released
      by slave.  Only effects program on first iteration.  */
   while (((GPIO_PADAT & 0x0200) ? 1 : 0) == 0){;}

      delay(2*D);  
       
      PADAT_init;
      SCL_low;
      delay(D); 
       
      out_mask >>= 1;
      count--;  
     }
     
     PADAT_init;
     SDA_high;  /* Let go of data pin. */
     delay(D); 
      
     if (((GPIO_PADAT & 0x0400) ? 1 : 0) == 1)
     { 
      status = 0xA1; /* Transfer complete, bus busy, acknowledge not received. */
      break; } /* If not acknowledged, exit loop. */
     
    PADAT_init;
     SCL_high;
     delay(2*D);  
   
     PADAT_init;
     SCL_low;
     status = 0xA0;  /* Transfer complete, bus busy, acknowledge received. */
     delay(D); 
     
     send_byte = buffer[i];      
    }
    
    PADAT_init;
    SDA_high;
    SCL_low;  
 delay(100);
 return(status);
}

/********************************************************************/

uint8 i2c_read(uint8 slave_address, uint8 *buffer, int byte_count, int freq)
{
 uint8 input_byte = 0x00;
 uint8 value = 0x00;
 uint8 out_mask = 0x80;
 uint8 status = 0x81;
 int count = 8;
 int clk_count = 0;
 int i = 0;
 
 /* Set delay value based on frequency. */
 int D = (int) ((4000/freq) - 14);
 
 slave_address = (slave_address | 0x01);
   
 i2c_start();
 delay(500);
               
 /**********  Write Address Procedure **********/
  
   while(count > 0)
   {
    value = ((slave_address & out_mask) ? 1 : 0);
     if (value == 1)
     {
      PADAT_init;
       SDA_high;}
     else
     {
      PADAT_init;
      SDA_low;}
      delay(D);      
                   
      PADAT_init;
     SCL_high;
      
     /* Clock stretching wait.  Wait until clock is released
     by slave.  */
     while (((GPIO_PADAT & 0x0200) ? 1 : 0) == 0){;}

     delay(2*D); 
       
     PADAT_init;
     SCL_low;
     delay(D);  
       
     out_mask >>= 1;
     count--;        
  }
     
    PADAT_init;
  SDA_high;  /* Let go of data pin. */
    delay(D);
    SCL_high;
    delay(2*D);  
   
    /* If not acknowleged, set status accordingly and exit read process. */
    if (((GPIO_PADAT & 0x0400) ? 1 : 0) == 1)
    {
     status = 0xA1;
     return(status);}
   
    PADAT_init;
    SCL_low;
    delay(D);
 
 /**********  Begin Read Procedure **********/
 
 /* Release SDA and SCL to initiate transfer. */
 PADAT_init;    
 SDA_high;
 SCL_high;

 for(i = 0; i < byte_count; i++)
 {
  count = 8;
  input_byte = 0x00;
   
  PADAT_init;
  SCL_high;
   
  /* Clock stretching wait.  Wait until clock is released
     by slave.  */
  while (((GPIO_PADAT & 0x0200) ? 1 : 0) == 0){;}
           
  /* Loop for bit-by-bit read of data. */
  while(count > 0) 
  {
    PADAT_init;
    SCL_high;
    delay(D);  
    delay(4); /* Required to make read and write clocks the same freq. */
    
   if ((GPIO_PADAT & 0x0600) == 0x0600)
    input_byte++;
  
   delay(D);  
   
   PADAT_init;
   SCL_low;
   delay(2*D); 
      
   if (count == 1)
    break;
   else  
    input_byte <<= 1;
  
   count--;
  }
 
  /* Write input byte to "read_buffer". */
  buffer[i] = input_byte;
    
  if(i == (byte_count - 1))
   break;
     
     /* Below is the acknowledge procedure. */     
     PADAT_init;
     SDA_low;
     delay(D);  
     SCL_high;    
  delay(2*D);  
   
     PADAT_init;
     SCL_low;
     delay(D);  
     SDA_high; 
     status = 0xA0; 
 }     
 
 /* Standard protocol calls for the last read byte to
    not receive an acknowledge from the master. */    
 PADAT_init;
    SDA_high;
    SCL_high;    
 delay(2*D); 
    
   PADAT_init;
   SCL_low;
   delay(D);  
   SDA_high;
   status = 0xA1;
   return(status);
}

/********************************************************************/

void i2c_start(void)
{
 int clk_count = 0;
 uint8 compare = 0x00;
 
 PADAT_init;  
 SDA_high;
 delay(100);
 
 PADAT_init;  
 SCL_high;
 delay(100);
 
 /* Clock stretching wait.  Wait until clock is released
    by slave.  */
 while (((GPIO_PADAT & 0x0200) ? 1 : 0) == 0){;}    
  
 PADAT_init;
 SDA_low;
 delay(100);
     
    PADAT_init;  
 SCL_low;
 delay(100);
} 

/********************************************************************/

uint8 i2c_stop(void)
{
 uint8 status = 0x00;
 int clk_count = 0;
  
 PADAT_init;
 SCL_low;
 delay(100);

 PADAT_init;
 SDA_low;
 delay(100);
   
    PADAT_init; 
 SCL_high;
 
 /* Clock stretching wait statement.  Wait until clock is released
    by slave.  */
 while (((GPIO_PADAT & 0x0200) ? 1 : 0) == 0){;}
      
 delay(100);
   
    PADAT_init; 
 SDA_high;
 status = 0x81; /* Set bus idle. */
 return(status);
}

/********************************************************************/

void delay(int value)
{
 int clk_count = 0;
 while (clk_count < value)
 {clk_count++;}
}

/********************************************************************/

不错，支持一下