Strange LCD Behavior

[chips123]

Greetings, I have been successfully using several different LCD modules from several different manufacturers. Of course, I ran into an issue. I have an existing circuit using a 16F676 that seems fine with a Densitron 8*2 display as well as a Powertip 8*2 display. I have a 16F684 circuit that works properly with the densitron display, but the powertip display seems to be putting garbage to line one only. If I have the program only clear the display, the display seems to be cleared, but it displays the first character of line one as a block with a flashing underline cursor in position 2. I have tried extending command us and data us as well as extending power up pauses. PBP 2.47 . Any clues? Thanks,Scott

[chips123]

OK. I got it to work as expected. I had no config commands regarding the comparators and analog inputs. I disabled the comparators and set the inputs to digital and both types of LCDs act the same. Then why did the Densitron LCD work OK without the CMCON0 and ANSEL config commands in the program at all ?? Any clue on this?