#include <stc89c51.h>
#include <intrins.h>
#include "source.h"

/*            5ms延時           */
void ms (void)
{  uchar i=20,j;
   do
   {  j=250;
      while(--j);
   }
   while(--i);     
}
/*            啟動I2C           */
void ic_start (void)
{  io=1;
   clk=1;
   nop;
   io=0;
   nop;
   clk=0;
   nop;
}
/*             停止I2C              */
void ic_over (void)
{  io=0;
   clk=0;
   nop;
   clk=1;
   nop;
   io=1;
   nop;
}
/*              應(yīng)答檢測             */
void check_ack (void)
{  io=1;
   clk=1;
   nop;
   clk=0;
   nop;
}
/*                應(yīng)答                */
void ack (void)
{  io=0;
   clk=1;
   nop;
   clk=0;
   nop;
}
/*                非應(yīng)答              */
void no_ack (void)
{  io=1;
   clk=1;
   nop;
   clk=0;
   io=0;
   nop;
}
/*                寫一個字節(jié)            */
void write_byte (uchar d)
{  uchar i=8;
   do
   {  if(d&0x80)
      {  io=1;
         clk=1;
         nop;
         clk=0;
         io=0;
         nop;
       }
       else
       {  io=0;
          clk=1;
          nop;
          clk=0;
          nop;
       }
       d<<=1;
    }
	while(--i);
}
/*                讀一個字節(jié)                */
uchar read_byte (void)
{  uchar i=8,d;
   io=1;
   do
   {  clk=1;
      nop;
	  d<<=1;
      if(io)
      {  d|=0x01;
         clk=0;
         nop;
      }
      else
      {  d&=0xfe;
         clk=0;
         nop;
      }
   }
   while(--i);
   return d;
}
/*                向I2C寫數(shù)據(jù)            */
void ic_write (uint add,uchar d)
{  uchar i,j;
   j=(uchar)add;
   i=(uchar)(add/256);
   i<<=1;
   i+=0xa0;
   ic_start();
   write_byte(i); 
   check_ack();
   write_byte(j);
   check_ack();
   write_byte(d);
   check_ack();
   ic_over();
}
/*                  從I2C讀數(shù)據(jù)               */
void ic_read (uint add,uchar len)
{  uchar i=0,j,k;
   j=(uchar)add;
   k=(uchar)(add/256);
   k<<=1;
   k+=0xa0;
   ic_start();
   write_byte(k);
   check_ack();
   write_byte(j);
   check_ack();
   ic_start();
   k|=0x01;
   write_byte(k);
   check_ack();
   do
   {  ic_data[i]=read_byte();
      ack();
      i+=1;
   }
   while(--len);
   ic_data[i]=read_byte();
   no_ack();
   ic_over();
}