The saga continues...
For a new design, I am using a PIC16F877A and trying to communicate serially with this same MP3 player - essentially running the same code that I had on the 628. You will recall that I "solved" my problem with the 628 design by moving my serial RX an TX pins from PORTA.0 and A.1 to B.6 and B.7. Bruce explained that my problem was due to A.0 and A.1 being Schmitt Trigger (ST) type buffers instead of TTL. I am assuming that what he is implying is that if your pin is a ST, you can not use it for serial communication. Is that correct?

For my new design on the 877a, I had intended to use pins E.1 and E.2 for communication but, alas, they are ST... I tried moving the serial comm to pins A.2 and A.3 which are TTL and still do not seem to be able to talk to the player. Right now, I am not using a MAX232, just going straight from the PIC pins to the TX and RX pins on the player - just as I am doing with the 628 design. It works on that board, but not on the 877. BTW, I am running both at 20 mHz.

Can anyone shed some light on this?
Thanks!