External eeprom writing problem

Dominik · Joined: 04 Aug 2007 Posts: 18

I'm using a PICDEM 2 Plus Demo Board with a PIC16F877A and I made a program to write on the 24LC256 eeprom on that board.
It's working very fine but now I made a circuit with another 24LC256 only and put all the components needed also and I try to write on that eeprom using the PIC on the demo board but it's not working. I tried to change the ports but nothing is written and I really don't understand why.
Can someone help me ?
Thanks

Dominik

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You left off the 4.7K pull-up resistors on SDA and SCL.
These resistors are built-in to PicDem2-Plus board on pins C4 and C3.
If you move the i2c to different pins, you must add pull-up resistors
on the new pins.

Dominik · Joined: 04 Aug 2007 Posts: 18

You're right PCM Programmer, the problem is coming from the resistors.
Thank you so much again.