I made a board to 'serialize' a graphic LCD via i2c; the mega168 is used and I used the typical ISP pins for general IOs too
The problem is that I fail to program the part when the LCd screen is on it's socket (avrdude checksum fails). It seems that one of the line gets 'hijacked' by the LCd and corrupts the programming.
Here is the schematic; I suspect the 'E' line to be problematic.
(Please ignore the VDD/V0 part, it's been reworked, as a few other things)
I've been thinking that maybe I could tie the LCd reset to the Mega reset, to make sure the LCd is in reset when the mega is programmed, but that would probably stops me from being able to reset the screen independently ...
Any suggestion ? I'm a stark newbie :D