In this business, you have to draw the hard line occasionally on problems like these, and unfortunately we have to make assumptions as you pointed out below. That's one of the engineering challenges we all face: making the right tradeoff when there are no great choices... I agree with you Mike - depending on the product and the circumstances, OSCCAL may or may not need to be refreshed periodically. For EMC considerations (especially in the susceptibility arena), it's things like properly knowing when and how to refresh a critical register that make life difficult... Chuck Mauro > -----Original Message----- > From: Mike Keitz [SMTP:mkeitz@JUNO.COM] > Sent: Friday, February 27, 1998 4:35 PM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: Oscillator calibration rewriting... > > On Thu, 26 Feb 1998 17:42:27 -0800 "Mauro, Chuck" > writes: > >Yes, it can be updated anywhere in your program. But, don't forget > to > >use a MOVWF OSCCAL at the very beginning of your program (@ address > 0) > >to establish the proper factory calibration (the data sheet explains > >this). It sounds like you are definitely experiencing a reset > >problem. > > You should keep the factory value somewhere else in your program (a > logistical nightmare), and periodically do movlw /movwf OSCCAL. > Second best would be to copy the factory value to RAM as well as to > the > OSCCAL register at the start of the program, then periodically copy it > back to OSCCAL. But if a glitch hits hard enough to trash the RAM, > this > won't work. > > > _____________________________________________________________________ > You don't need to buy Internet access to use free Internet e-mail. > Get completely free e-mail from Juno at http://www.juno.com > Or call Juno at (800) 654-JUNO [654-5866]