How to read eeprom card (telephone card) using PIC?

[Einly]

I am using PIC 16f876 to read a telecard. I tried using i2c_read() to read it but the program hang. I suspect it is waiting for something to happen.

Below is my program:
#ifndef EEPROM_SDA

#define EEPROM_SDA PIN_C5
#define EEPROM_SCL PIN_C4

#endif

#include <16f876.h>
#use delay(clock=20000000)
#fuses hs, nowdt, nolvp, noprotect
#use rs232(baud=115200,xmit=PIN_C6,rcv=PIN_C7,PARITY=N)

#byte PORTB=6
#byte PORTC=7

#use i2c(master,sda=EEPROM_SDA, scl=EEPROM_SCL)

#define EEPROM_ADDRESS byte
#define EEPROM_SIZE 256

void init_ext_eeprom();
void write_ext_eeprom(byte MSB_address, byte LSB_address, byte data);
byte read_ext_eeprom(byte MSB_address, byte LSB_address);
byte i;

void main()
{
byte MSB, LSB, data0;
byte result1;
byte b=0x53;

set_tris_b(0);
set_tris_c(0x84);
portc=0;

init_ext_eeprom();
output_high(PIN_B7);
delay_ms(1000);
output_low(PIN_B7);

do
{
printf("%x\n\r",b);
for(i=0;i<64;i++)
{
result1=read_ext_eeprom(0,i);
printf("%x \r",result1);
delay_ms(300);
}

}while(1);
}


void init_ext_eeprom() {
output_float(eeprom_scl);
output_float(eeprom_sda);
}


void write_ext_eeprom(byte MSB_address, byte LSB_address, byte data) {

i2c_start();
i2c_write(0xa0);
i2c_write(MSB_address);
i2c_write(LSB_address);
i2c_write(data);
i2c_stop();
delay_ms(11);
}


byte read_ext_eeprom(byte MSB_address,byte LSB_address)
{
byte data2;

i2c_start();
i2c_write(0xa0);
i2c_write(MSB_address);
i2c_write(LSB_address);
i2c_start();
i2c_write(0xa1);
data2=i2c_read(0);
i2c_stop();
return(data2);
}

I connect PIN C5 to SDATA of the telecard, PIN C4 to the SCLK of the telecard. Vcc of the telecard to 5V and GND to 0V.

My I know what should I do to correct my mistake? Can I use this method? Is there any address on the telecard that could not be read?

Thanks
_________________
Einly

[Mark]

Those are probably smart cards.

[Kasper]

not knowing the cards, do you have your pull up resistors on the SDA and SCL lines? .. 3.3K or so

[Mark]

http://www.sspsolutions.com/files/Introduction_to_Smart_Cards.pdf

Here is some code to read using a basic stamp

http://www.elecdesign.com/Articles/Index.cfm?AD=1&ArticleID=6229