Of coarse I covered the window. By everything I could, including multiple layers of black tape and my finger. Everything I described relates to a PIC with covered window. Well, anyway, PIC didn't solve the original project's problem, so I had to use Scenix... Gennady Palitsky gennadyp@mainlink.net -----Original Message----- From: Scott A. Woods To: PICLIST@MITVMA.MIT.EDU Date: Monday, May 18, 1998 5:37 PM Subject: Re: Windowed part works, OTP don't >Gennady, > >The obvious difference between an OTP & a windowed part is the window. If you leave the >window uncovered you will get leakage from photon induced carriers - this may be enough >to cause the differences indicated below. Try covering the window or shining brighter, >more UV light, on a windowed part & see what effect that has. A covered windowed part >ought to behave the same as the OTP. > >Scott > >---------- >> From: Gennady Palitsky >> To: PICLIST@MITVMA.MIT.EDU >> Subject: Re: Windowed part works, OTP don't >> Date: Monday, May 18, 1998 12:16 PM >> >> -----Original Message----- >> From: George A. Silvis >> To: PICLIST@MITVMA.MIT.EDU >> Date: Monday, May 18, 1998 11:45 AM >> Subject: Windowed part works, OTP don't >> >> >> >'m having trouble with the PIC16C924 part. The code works in the windowed >> >part but won't run when I put it in an OTP part. I'm using the Picstart to >> >do the programming. >> > ... >> >George ... >> >> I had this problem with 16C71. It worked for a windowed part, but not for an >> OTP. All Microchip could tell me is that it's exactly the same die, so it >> shouldn't be any difference. I did make sure that all registers are >> initialized at start-up. >> Even more weird - OTP worked when I lifted VDD pin! >> Finally I've found the problem - one of inputs had about 3.4V rails on it. >> When I raised it to 5V, everything came to normal. It looks like specs for >> reprogrammable and OTP parts are not exactly the same. >> Another thing they told me to check: voltage on any pin should not be higher >> that VDD - it can cause latch-up. But I think it would be the same for both >> parts? >> I hope it may help a bit. >> >> Gennady Palitsky >> Jefferson Audio Video Systems >> gennadyp@mainlink.net