James Newtons Massmind wrote: > I've been sucked into an old project with 16C54 and a 16C57 on board > and the code is just... Well, lets just say Olin would probably be > violently sick if he had to look at this. It was written then modified > to hit a moving spec and then patched by at least two different people. > Pure hell. > > ... > > Trying to figure out what is going on in this code is just beyond me. > Bad thing have happened inside my brain as a result of trying. > > ... > > It isn't worth re-writing the old PIC code. Are you sure? I just checked the ancient scrolls, and the 16C54 only has 512 instructions. Starting with the spec and a clean slate might be exactly the way to go to get to the end result more quickly, economically, and with more confidence. Just trying to understand the existing code alone would probably take as long or longer than just creating new code to match the spec. Is the new code going onto existing boards with the old chips on them, or newly manufactured boards of the old design? If the latter, then you could substitute a 16F627A for the 16C54. It has the same pinout, is easier to develop with, has more memory, and most likely costs less. Developing for the 16F627A family is easy because it is supported by the ICE-2000. If you've got a good spec, I can give you a fixed price quote for developing the firmware on a 16F627A. > So: Is there a PIC that has ICD capability that is a pin for pin > replacement for the x54 or x57 other than the SX? > > Is there a reasonably low cost way to emulate a x54 or x57? The '54 is no problem, but you're screwed with the '57. That 28 pin footprint is in the same "Huh? We never did that" catagory as the PIC 17. Again, it comes down to what you are trying to preserve, the cost of that, and the cost of updating. You could make an adapter board to emulate the 16C57 footprint from a more modern processor, like 16F876A or 18F252. Or you could respin the board changing only the processor pinout. Or you could go straight to the new design and save money trying to make the dinosaur hop along a few more paces. ****************************************************************** Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC consultant in 2004 program year. http://www.embedinc.com/products -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist