At 06:17 AM 4/12/00 , you wrote: > > Yes, that would do it. > >Changed the PIC - same story. > > > > Dumb question, is this particular pic specified to run at this low voltage > > and at this xtal speed? > >Oh bugger. I had naively taken it for granted that the quoted' wide >operating range of 2.0 to 5.5V' was for all operating speeds... and looking >at the datasheet it seems this isn't the case.. > >According to the datasheet, I'll need at least 4.5V. I think you may have >hit the nail on the head! Local ex-PIC rep claims to have a customer with 5 Million or so 16C57's running at 20 MHz AND 3.3 volts. But data sheet indeed says 4.5 volts is minimum. Fortunately I can translate to a Scenix chip if this turns into a real problem. Same driving issues though--memory I need is available only in 3.3 volt. Any one have any confirming experience? There is a CMOS series 74LVXnnnn ( I think--maybe it was 74LCX)) that will take power at 3.3 volts (and output at 3,3 volts), but inputs to at least 7 volts. Great for interfacing in this type of situation. Kelly William K. Borsum, P.E. -- OEM Dataloggers and Instrumentation Systems & San Diego, California, USA