need help!! on 24lc256 EEPROM

[Mk]

I am using a 24lc256 eeprom, can someone tell me how to declare the address for write_ext_eeprom() and read_ext_eeprom() functions; ex:

write_ext_eeprom(1, 9);
a = read_ext_eeprom(1);

is this able to work???

thanks for the help!!

/////////////////////// MY PREVIOUS POSTING ////////////////////////////
hi! i am trying to get my fisrt eeprom program work. my LCD and Keypad sections are working ok, but after i added an eeprom program, i could not get it through, it has stuck on writing to the eeprom.

in 24256.c program i make few changes:
#define EEPROM_SDA PIN_C4
#define EEPROM_SCL PIN_C3
i also added pull-up 2.2k resistors on both pins.

here is my program:

#define(__PCM__)
#include <16f877a.h>
#fuses HS, NOWDT, NOPROTECT, PUT, BROWNOUT, NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600,xmit=PIN_C6, rcv=PIN_C7, errors)
#include "lcdd.c"
#include "kbdb.c"
#include "24256.c"

main()
{
char k,a;
init_ext_eeprom();
lcd_init();
kbd_init();
lcd_putc("\fReady 05 !\n");

while (True)
{
k=kbd_getc();

if (k!=0)
{ lcd_putc('k');
lcd_putc(k);
if (k=='*')
lcd_putc('\f');
else
{
lcd_putc('y');
lcd_putc(k); <------ i can see the ouput from LCD here
write_ext_eeprom(1, 9);
a = read_ext_eeprom(1);
lcd_putc('p'); <---- but never reach the ouput "p" on the LCD
and the program stops
lcd_putc(a);
}
}
}
}

please help! thanks!

[PCM programmer]

I think you should find the exact line of source code in the
24256.C file that is causing the program to lock-up.

If you have ICD2, you could use breakpoints to find
the line of code.

If you don't have ICD2 or another debugger, then you
could put a lcd_putc() statement between each line of
code in a suspected routine. Example:

[Haplo]

I had exactly the same problem yesterday, my code got stuck on writing to 24256. It turned out that my pull-up resistor on the SCL line was not making proper connection. Make sure you have pull-ups on both SCL and SDA lines, and they are connected properly.

[Mk]

Thanks the help!!!!
i found the problem! first of all, many thanks to PCM programmer and Haplo.

i did use PCM's method to debug my codes and the program returned the key word, and i tried the suggestion from Haplo to check my connections, finally, i found my ground bus on the breadboard didn't connect to power supply..MMMmmmmy GOD!!!!. how can i make such mistake#@#%!... it took me two days to find out. anyway, now i am so happy my fisrt eeprom program is working~ i can move on to next step....

thanks again!!!

[Haplo]

Yeah, I've done this one too. Once I forgot to connect one ground row of my breadboard to the power supply. The two ground pins of PIC16F870 were making the only ground path between two rows. After powering up the board I noticed my VCC dropped from 5.0v to 4.6v immediately, and kept dropping slowly afterwards until it reached 4.0v where almost everything stopped working. I was impressed that the PIC didn't smoke.

[Guest]

i have the other question, now i try to locate a data from an eeprom address, if i do like below i can retrieve the data from the eeprom address:
write_ext_eeprom(1, 9);
a = read_ext_eeprom(1);

but if i assign a variable:
char k,a;
k=kbd_getc();
a = read_ext_eeprom(k);
lcd_putc(a);

from keypad input i enter: 1
but lcd didn't show 9, i found the eeprom address is "Long int" data type,
so i tried to convert "char" data type into "long int" data type by using:

long int j;
char a,k;

k=kbd_getc();
j=k;

a = read_ext_eeprom(j);
lcd_putc(a);

but this way didn't work either, so my question is how to convert a "char" data type into "long int" data type?

thanks!!

[PCM programmer]

[Mk]

thank you PCM programmer, my program is working again>>>

[MK]

can someone give me a direction or example, how to create a look up table and store in eeprom?

ex.

address ------------ Data 1(name) ------------ Data 2 (score)
-------------------------------------------------------------------------
0001----------------- Mike Corson ------------------ 62
0002 ---------------- John Greene ------------------ 95
- - -
- - -
9999---------------- Richard Campbell------------- 100


thanks!!