"J. Cabral" wrote: > >Did you examine the contents of TRISA and PORTA to see if the > > bits actually changed? Yes they changed! If the bit in porta changed, but the pin did not, the most likely explanation is that you were probing the wrong pin. The value seen in the porta register when it is read reflects the signal level on the pin, not the state of the the output latch, so if the porta register says the pin is changing, but the scope does not, then there is no electrical connection between the pin and the scope. Try setting ALL the porta pins to outputs, and alternately write 0 and FF to porta - then you have 8 pins flapping up and down - much easier to see! Ok, so there aren't 8 bits in porta. What the heck. The principle applies. Clyde -- Clyde Smith-Stubbs | HI-TECH Software, | Voice: +61 7 3354 2411 clyde@hitech.com.au | P.O. Box 103, Alderley, | Fax: +61 7 3354 2422 http://www.hitech.com.au | QLD, 4051, AUSTRALIA. | --------------------------------------------------------------------------- Download a FREE beta version of our new ANSI C compiler for the PIC microcontroller! Point your WWW browser at http://www.hitech.com.au/