i2c and pcf8583 rtc

[mati]

Hi
I used I2C routines from I2C tutorial to real time clock pcf 8583 and it not working. It shows 00:00:00 and i don't know why. My device is PIC18f4550 and i use c18 compiler. Can You help me?
This is my code:

Code: Select all

#include <p18cxxx.h>       
#include <stdio.h>
#include <delays.h>

#define SDA    TRISAbits.TRISA3
#define SCL    TRISAbits.TRISA4
#define SDA_IN    PORTAbits.RA3
#define SCL_IN    PORTAbits.RA4



void i2c_init (void)
{
   SDA = SCL = 1;
   SCL_IN = SDA_IN = 0;
}

void i2c_delay (void)   
{
   Delay10TCYx(1);     //delay 10 instruction cycles
}
   
void i2c_start(void)
{
   SDA = 1;             // i2c start bit sequence
   i2c_delay();
   SCL = 1;
   i2c_delay();
   SDA = 0;
   i2c_delay();
   SCL = 0;
   i2c_delay();
}
   
void i2c_stop(void)
{
  SDA = 0;             // i2c stop bit sequence
  i2c_delay();
  SCL = 1;
  i2c_delay();
  SDA = 1;
  i2c_delay();
}

unsigned char i2c_read (char ack)     // 1-ack, 0-nack
{
unsigned char x, d=0;

  SDA = 1;
  for(x=0; x<8; x++) {
    d <<= 1;
    do {
      SCL = 1;
    }
    while(SCL_IN==0);    // wait for any SCL clock stretching
    i2c_delay();
    if(SDA_IN) d |= 1;
    SCL = 0;
  }
  if(ack) SDA = 0;
  else SDA = 1;
  SCL = 1;
  i2c_delay();             // send (N)ACK bit
  SCL = 0;
  SDA = 1;
  return d;
}

char i2c_send (unsigned char d)
{
unsigned char x;

   for(x=8; x; x--) {
      i2c_delay();
      if(d&0x80) SDA = 1;
      else SDA = 0;
      SCL = 1;
      i2c_delay();
      d <<= 1;
      SCL = 0;
   }
   i2c_delay();
   SDA = 1;
   SCL = 1;
   i2c_delay();   
   x = SDA_IN;                   
   SCL = 0;
   return x;
}
   
char sec, min, hr, day, mth, year;

void fromi2c (void)
{
   i2c_start();
   i2c_send(0xA0);
   i2c_send(0x02);
   i2c_start();
   i2c_send(0xA1);
   sec=i2c_read(1);
   min=i2c_read(1);
   hr=i2c_read(1);
   day=i2c_read(1);
   mth=i2c_read(0);
   i2c_stop();
}
   

void usart(void)
{

TRISCbits.TRISC7=1;
TRISCbits.TRISC6=1;

TXSTA=0b00101110;
RCSTA=0b10010000;
BAUDCON=0;
SPBRG=129;      //baud=9600
}



void main(void)
{

   while(1)
   {
   usart();
   i2c_init();
   odi2c();   

   printf("\r%02x:%02x:%02x\r", sec, min, godz);
   
   }
}