I have several Tap-28 development boards I have used numerous times and have an LCD on a daughter board that plugs into the headers on the Tap-28 board. I have connected to it on PortB. Been hacking at it off and on most of Friday but couldn't get the LCD to display correctly. Have checked ALL my connections between the daughter board and the LCD but no issues found.That was my first mistake, going from the daughter board to the LCD pins. Decided to check continuity between the actual header connections on the development board and the LCD.
BAM!! the B.7 pin was never soldered. I couldn't have ever used this pin in the past as it was never soldered but I have used the second and third Tap28 board as well.
Some of the simplest issues come and bite you in the rear.. Its the simple ones that are the hardest to solve it seems like.