At 08:07 23/06/98 +0200, you wrote: >Hi guys, > >could you tell me what the 16C559 is? (EEPROM/RAM size, word size, pins, >etc.) >It is not in may catalogue... > >Imre Mistyped 16C558 I'd say. I think that is what is been taken for granted. Jim > >On Mon, 22 Jun 1998, Caisson wrote: > >> > Van: John P. Leonard >> > Aan: PICLIST@MITVMA.MIT.EDU >> > Onderwerp: Do 16C559/JW's get tired? >> > Datum: vrijdag 19 juni 1998 21:06 >> > >> > I've been using a couple of 16C559/JW's (windowed EPROM's) for >> prototyping >> > and it appears that after several write/erase cycles, the PIC's will no >> > longer start-up if Vcc is < 4.8V. At the beginning of the day, they will >> > fire-up with Vcc=3.6 (they're rated to operate down to 2.5V); but a >> couple >> > hours and several write/erase cycles later and they won't start-up unless >> > I set Vcc to nearly 5V. >> > >> > I observed this several days ago, also. The configuration bits aren't >> > being changed. Are Mulder & Scully still subscribed to the list? >> > Anybody else been down this weird path? >> > >> > John >> >> Hello John, >> >> I think your PIC suffers from the Memory-effect on the individual >> EPROM-cells. >> This means that "unknown logic level" voltage widens (A Zero-state is not >> from 0.0 thru 0.7 volts, but only to 0.5 volts for example. The High-state >> suffers the same problem). Heat (dissipation of the PIC itself or >> otherwise) will worsen those >> problems, because resistance will get higher. >> >> Solution : allways over-erase the pic. >> >> If you have a professional programmer try to verify your PIC at a low >> voltage. It will probably fail ... >> >> Greetz, >> Rudy Wieser >> >> >