I am trying to use the parallel slave port on a 16F877 to recieve data from another chip like it. I have put my own a master program in one, and a slave program in another. The master program directly manipulates the ~WR, ~CS and port pins directly, according to the waveform order shown in AJN579 or the '877 data sheet, or as close as I can. Right now, whether or not it works seems to depend on chance, power on circumstances. The first powerup rarely works but if the power flickers or something, sometimes the slave is actually responding. I have not been able to get the slave uChip to work at all using the code I downloaded that was associated with AN579. Hints? Thanks! Jeff -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu