Eric:
We had all the things you suggested. A high quality reset generator, drivers on I/O lines and pullup & pulldowns where required. The LCD controller from the clients first supplier worked great. Early in production they came up with a 2nd source display module that was 20% lower cost. It would display stray characters on the display each time the device powered up. We never really were able to figure this out except that if the microcontroller could have done the software reset of the LCD module soon enough the customer would not have seen the stray characters. However in this case the product used a CPU with a PLL. There was a 0.15 to 0.25 second time for the PLL to start up and get running. Then the software had to first run a BIT (built in test) consisting of a RAM test and a FLASH checksum routine before it could do anything else. These tests added about another 0.1 second to the time stray characters were visible on the LCD display. The PNP transistor was the only solution we could find. :-(

Michael Karas