ds2433.c

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/*
  CodeVisionAVR C Compiler
  (C) 1998-2004 Pavel Haiduc, HP InfoTech S.R.L.

  Dallas Semiconductor DS2433 1 Wire bus EEPROM functions
*/

#include <delay.h>

// selects a specific DS2433 on the bus
// if romcode is NULL then only one 1 Wire device can be used
unsigned char ds2433_select(unsigned char *romcode)
{
unsigned char i;
if (!w1_init()) return 0;
if (romcode)
   {
   w1_write(0x55);
   for (i=0;i<8;i++) w1_write(*romcode++);
   }
else return w1_write(0xCC);
}

// read a block of size bytes starting from memory address addr
// and stores it at dest
// returns 1 if succesful, 0 if not
unsigned char ds2433_read_block(unsigned char *romcode,
unsigned char *dest,unsigned int addr,unsigned int size)
{
if (!ds2433_select(romcode)) return 0;
w1_write(0xF0);
if (!w1_write(*(unsigned char *) &addr)) return 0;
if (!w1_write(*((unsigned char *) &addr+1))) return 0;
while (size--) *dest++=w1_read();
return 1;
}

// read a byte from memory address addr and stores it at data
// returns 1 if succesful, 0 if not
unsigned char ds2433_read(unsigned char *romcode,
unsigned int addr,unsigned char *data)
{
return ds2433_read_block(romcode,data,addr,1);
}

// write a block of size bytes, located at source,
// starting from memory address addr
// returns 1 if succesful, 0 if not
unsigned char ds2433_write_block(unsigned char *romcode,
unsigned char *source,unsigned int addr,unsigned int size)
{
unsigned char al,ah,es,i;
unsigned char *p;
while (size)
      {
      // write data to the scratchpad
      if (!ds2433_select(romcode)) return 0;
      w1_write(0x0F); 
      w1_write(al=*(unsigned char *) &addr);
      w1_write(ah=*((unsigned char *) &addr+1));
      p=source;
      // write a page
      while (1)
            {
            w1_write(*source);
            es=(unsigned char) addr & 0x1F;
            ++addr;
            ++source;
            --size;
            // test if the scratchpad is full
            // or the block is finished
            if ((es==0x1F) || (size==0))
               {
               // verify scratchpad data
               if (!ds2433_select(romcode)) return 0;
               w1_write(0xAA);
               if (al!=w1_read()) return 0;
               if (ah!=w1_read()) return 0;
               i=w1_read();
               if (((i & 0x1F)!=es) || (i & 0xA0)) return 0;
               for (i=(al & 0x1F);i<=es;i++)
                   if (w1_read()!=*p++) return 0;
               // copy the scratchpad to EEPROM
               if (!ds2433_select(romcode)) return 0;
               w1_write(0x55);
               w1_write(al);
               w1_write(ah);
               w1_write(es);
               delay_ms(5);
               break;
               };
            };
      };
return 1;
}

// write the byte data at memory address addr
// returns 1 if succesful, 0 if not
unsigned char ds2433_write(unsigned char *romcode,
unsigned int addr,unsigned char data)
{
return ds2433_write_block(romcode,&data,addr,1);
}