Then break it back down to PortD only...and build 'er back up...
Just do a 'blinky' on all pins on PortD...
Code:
DEFINE OSC 4
@ DEVICE pic16f877a, CPD_OFF
@ DEVICE pic16f877a, PROTECT_OFF
@ DEVICE pic16f877a, WRT_OFF
CLEAR : ADCON1=7 : INTCON=0 : B0 var byte : trisd = 0
main: b0 = b0 + 1 : portd = b0 : goto main
You should see each Port D pin flashing at exactly half the frequency of the pin before it. If it's flashing too fast, throw a bit of a pause in the main loop. At least that'll take any questions about PortD out the window...