Post by thread:Problem with 16C57

I am experiencing a problem with the 16C57. Code written for a '56 works fine with our project when used with a '56. When this code is put into a '57 (more ports were needed), without modification, it does not run. I understand there may be some less adequately documented problems with the '57 in terms of initialization and such. Can anyone shed some light on this ? By the way, all the parts are the EPROM variety. Thanks, Stephen Dunifer

I had a problem with the '57 which was undoubtedly carelessness on my part, which may be your cause, the problem was the FSR register, I forgot to clear it on power up thus the program would write to the wrong parts of paged memory. Unfortunately the page select bits in my development /JW part always cleared to zero on power up, and MPSIM always placed FSR in to a zero state as well, so the program worked perfectly! As soon as I programmed OTP parts the program failed at random as these devices didn't exhibit the same lucky tendancy as my /JW part to zero the page select bits. I think it is unlikely, but *just* possible that you also have some kind of similar initialisation problem, but even if not this may act as a warning for other developers ! Robin (spam_OUTrobin.abbottTakeThisOuTdial.pipex.com)

Stephen Dunifer <.....frbspdKILLspam@spam@CRL.COM> wrote: >I am experiencing a problem with the 16C57. Code written for a '56 >works fine with our project when used with a '56. When this code is put >into a '57 (more ports were needed), without modification, it does not >run. I understand there may be some less adequately documented problems >with the '57 in terms of initialization and such. Can anyone shed some >light on this ? Stephen: My guess is that you have a short loop at the start of your program which clears all registers. Is that true? If so, it's unlikely that it'll work on the 16C57. If you need a 16C57 "Clear-Registers" routine, let me know; I've gotten tired of posting it to the list. Also, keep in mind that the FSR is not initialized on power-up; you should make sure that bits 5 and 6 are clear before you use the FSR to indirectly access registers on page 0. -Andy -- Andrew Warren - fastfwdKILLspamix.netcom.com Fast Forward Engineering, Vista, California

Just thought of the REAL reason Stephen's "unmodified" code stops working when he loads it into a 16C57 instead of a 16C56: The Reset Vector is at 03FF on the 16C56. On the 16C57, it's at 07FF. -Andy -- Andrew Warren - .....fastfwdKILLspam.....ix.netcom.com Fast Forward Engineering, Vista, California

>>I am experiencing a problem with the 16C57. Code written for a '56 > My guess is that you have a short loop at the start of your program which > clears all registers. Is that true? If so, it's unlikely that it'll work > on the 16C57. If you need a 16C57 "Clear-Registers" routine, let me know; > I've gotten tired of posting it to the list. Clearing all registers only requires little code (10 or so instructions) and seems a good thing to do as a matter of routine. Frank "Mutual respect, even if we disagree." ------------------------------------------------------------------------ Frank A. Vorstenbosch +31-(70)-355 5241 EraseMEfalstaffspam_OUTTakeThisOuTxs4all.nl