Hi.

I'm trying to program the eeprom in a pic12ce519 using the following code.
Doesn't work, though. Someone care to have a look?

/*
    IIC BUS INTERFACE:

    Code size for one read and one write to IIC device:

        8 MHz clock   : 110 instructions
        4 MHz clock   : 91 instructions
        2 MHz clock   : 82 instructions
        500 kHz clock : 76 instructions

    Use of macros are recommended. This module use
    subroutines in one level. New macros may be
    constructed in a similar way.

    Delay syntax:
      delay_4us_m3 : insert a 4 microseconds delay, but subtract the
                     time to execute 3 instruction cycles

    1 instruction cycle = 4 clock cycles = 1 microsecond at 4 MHz
*/

#include <12ce519.h>

void delay_ms(uns16 number){

        int a,b;
        uns16 c;
        for(a=0;a<number;a++)
        {

                for(c=0;c<166;c++)
                {
                    #asm
                    nop
                    #endasm
                }

        }
}


void blink( void )
{

        GPIO.5 = 0;             // Turn LED on.
        delay_ms(500);          // Delay half a second.

        GPIO.5 = 1;             // Turn LED off.
        delay_ms(500);
}


  #define Clock_4MHz

  #pragma  bit  scl_IIC    @ 6.7
  #pragma  bit  sda_IIC    @ 6.6

  #define  WRITE_sda()     sda_IIC = 0
  #define  READ_sda()      sda_IIC = 1

  #define  IIC_address_RW_0   0xa2
  #define  IIC_address_RW_1   0xa3

  char  IIC_byte;
  bit   IIC_error, master_ack;


  #define  delay_4us_m1   nop();nop();nop();
  #define  delay_4us_m3   nop();
  #define  delay_4us_m6
  #define  delay_4us_m7
  #define  delay_4us_m8
  #define  delay_5us_m1   nop();nop();nop();nop();
  #define  delay_5us_m2   nop();nop();nop();
  #define  delay_5us_m5
  #define  delay_5us_m7
  #define  delay_5us_m10
  #define  delay_0us_m1

void startIICcomm( void)
/* assuming sda_IIC = 1  and  scl_IIC = 1 */
{
    sda_IIC = 0;
    delay_5us_m10
}


void stopIICcomm( void)
{
    scl_IIC = 0;
    WRITE_sda();
    sda_IIC = 0;
    delay_5us_m1
    scl_IIC = 1;
    delay_4us_m1
    sda_IIC = 1;
    delay_4us_m6
}


void readIICbus( void)
/* reads one byte from IIC slave device */
{
    char  counter;

    scl_IIC = 0;
    READ_sda();
    counter = 8;
    do  {
        scl_IIC = 0;
        delay_5us_m1
        scl_IIC = 1;
        delay_4us_m7
        Carry = sda_IIC;
        IIC_byte = rl( IIC_byte);
    } while ( -- counter > 0);

    scl_IIC = 0;
    sda_IIC = master_ack;
    delay_5us_m7
    scl_IIC = 1;
    delay_4us_m6
}


void sendIICbyte( char W)
/* writes one byte to IIC slave device */
{
    char  counter;

    IIC_byte = W;
    counter = 8;

    do  {
        IIC_byte = rl( IIC_byte);
        scl_IIC = 0;
        delay_5us_m5
        sda_IIC = Carry;
        delay_0us_m1   /* minimum 250 nanosec. */
        scl_IIC = 1;
        delay_4us_m3
    } while ( -- counter > 0);

    /* read ack. */

    scl_IIC = 0;
    READ_sda();
    delay_5us_m2
    scl_IIC = 1;
    if ( sda_IIC)
        IIC_error = 1;
    delay_4us_m8
}


#define  readByteFromIIC( address, variable)     \
    startIICcomm();                              \
    sendIICbyte( IIC_address_RW_0);              \
    sendIICbyte( address);                       \
    stopIICcomm();                               \
                                                 \
    startIICcomm();                              \
    sendIICbyte( IIC_address_RW_1);              \
                                                 \
    /* more bytes to read ..                     \
      master_ack = 0;                            \
      readIICbus();  */                          \
                                                 \
    master_ack = 1;                              \
    readIICbus();                                \
    stopIICcomm();                               \
    variable = IIC_byte


#define  writeByteToIIC( address, IIC_data)      \
    startIICcomm();                              \
    sendIICbyte( IIC_address_RW_0);              \
    sendIICbyte( address);                       \
                                                 \
    sendIICbyte( IIC_data);                      \
    /* + more bytes to send                      \
      sendIICbyte( .. ); */                      \
                                                 \
    stopIICcomm();

/* NOTE: EEPROM's require a delay between each
         (or each second) write to IIC device */


 void main( void)
 {
        #asm
    MOVLW   0x1F                                // Set the OPTION register
    OPTION
    MOVLW   0x0F
    TRIS    GPIO
        #endasm

     char x;
     writeByteToIIC(10, 100);
        blink();                        // delay
     readByteFromIIC(10, x);

        if(x==100)
        {
                while(1)
                        blink();                        /* this is what I
 want... */ }
        else
        {
                while(1)
                        GPIO.5=0;               /* Program flow ends up here.
 :(  */ }
 }


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--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.