ds1307 from f877 to f452 not work

[microkam]

this code is run ok on 16f877,when i download this code on 18f452 there is one problem that the ds1307 not work, in the same time the 24lc256 on the same bus is working good...whats the problem!!!!


define osc 4
DEFINE LOADER_USED 1

DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTB
DEFINE LCD_RSBIT 3
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 2
DEFINE LCD_BITS 4
DEFINE LCD_COMMANDUS 2000
DEFINE LCD_DATAUS 50
DEFINE LCD_LINES 2


DPIN var PORTC.4 'I2C DATA PIN 24LC256 and ds1307,with 4K7 pull up
CPIN var PORTC.5 'I2C CLOCK PIN with pulled up resister 4K7


add var word
d1 var byte
d2 var byte
B0 var byte
sec var byte
sec0 var byte
sec1 var byte
rtcco var byte
rtcad var byte

pause 500
rtcco=$D0
rtcad=0
B0=0
I2CWRITE DPIN,CPIN,rtcco,rtcad,[B0,B0,B0,B0,B0] ' intilization of ds1307
lcdout $FE,1," start"
main:
pause 1000
add=0
d1=9
I2cWRITE DPIN,CPIN,$A0,add,[d1] 'eeprom write
pause 30
I2CREAD DPIN,CPIN,$A1,add,[d2] 'eeprom read
gosub readtime
lcdout $FE,1,#d2," ",#sec
goto main

readtime:
rtcco=$D0
rtcad=0
I2CREAD DPIN,CPIN,rtcco,rtcad,[B0] 'ds1307 read
sec0=B0&%00001111
sec1=B0&%01110000 : sec1=sec1>>4
sec=sec0+sec1*10
return