9366.c

The firmware driver in C for the EEPROM Mimcro-Wire 95xx series.

///////////////////////////////////////////////////////////////////////////
////   Library for a MicroChip 93C66 configured for a x8 org           ////
////                                                                   ////
////   init_ext_eeprom();    Call before the other functions are used  ////
////                                                                   ////
////   write_ext_eeprom(a, d);  Write the byte d to the address a      ////
////                                                                   ////
////   d = read_ext_eeprom(a);   Read the byte d from the address a    ////
////                                                                   ////
////   The main program may define eeprom_select, eeprom_di, eeprom_do ////
////   and eeprom_clk to override the defaults below.                  ////
////                                                                   ////
///////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////

#ifndef EEPROM_SELECT

#define EEPROM_SELECT PIN_B7
#define EEPROM_CLK    PIN_B6
#define EEPROM_DI     PIN_B5
#define EEPROM_DO     PIN_B4

#endif

#define EEPROM_ADDRESS long int
#define EEPROM_SIZE    512

#define hi(x)  (*(&x+1))


void init_ext_eeprom() {
   BYTE cmd[2];
   BYTE i;

   output_low(EEPROM_DI);
   output_low(EEPROM_CLK);
   output_low(EEPROM_SELECT);

   cmd[0]=0xc0;
   cmd[1]=0x4;

   for(i=1;i<=5;++i)
      shift_left(cmd,2,0);
   output_high(EEPROM_SELECT);
   for(i=1;i<=12;++i) {
      output_bit(EEPROM_DI, shift_left(cmd,2,0));
      output_high(EEPROM_CLK);
      output_low(EEPROM_CLK);
   }
   output_low(EEPROM_DI);
   output_low(EEPROM_SELECT);
}


void write_ext_eeprom(EEPROM_ADDRESS address, BYTE data) {
   BYTE cmd[3];
   BYTE i;

   cmd[0]=data;
   cmd[1]=(BYTE)address;
   cmd[2]=0xa|hi(address);

   for(i=1;i<=4;++i)
      shift_left(cmd,3,0);
   output_high(EEPROM_SELECT);
   for(i=1;i<=20;++i) {
      output_bit(EEPROM_DI, shift_left(cmd,3,0));
      output_high(EEPROM_CLK);
      output_low(EEPROM_CLK);
   }
   output_low(EEPROM_DI);
   output_low(EEPROM_SELECT);
   delay_ms(11);
}


BYTE read_ext_eeprom(EEPROM_ADDRESS address) {
   BYTE cmd[3];
   BYTE i,data;

   cmd[0]=0;
   cmd[1]=(BYTE)address;
   cmd[2]=0xc|hi(address);

   for(i=1;i<=4;++i)
      shift_left(cmd,3,0);
   output_high(EEPROM_SELECT);
   for(i=1;i<=20;++i) {
      output_bit(EEPROM_DI, shift_left(cmd,3,0));
      output_high(EEPROM_CLK);
      output_low(EEPROM_CLK);
      if(i>12)
        shift_left(&data,1,input(EEPROM_DO));
   }
   output_low(EEPROM_SELECT);
   return(data);
}