>From the PDF file MOVLW k Move Literal to W 1100 kkkk kkkk Looks like 0xC 9 0 is the right thing for MovLW 0x90 to me As you could have several different 509/JW's with different OscCal values, I'd suggest you write the number down on the underside of the PIC chip before erasing it for the first time. Need to do that to the 508/JW and 509/JW here that Richard loaned me Someone suggested one of those metallic inks, I think I'd suggest a good *permanent* ink at any rate! You don't want to lose that info! And, don't code protect /JW parts, it's not worth the fight even if you CAN unprotect 'em Mark Graham North wrote: > > Does the value 0xC90 sound correct? > > Is the 0xC part is the hex for movlw? > > ---------- > From: Jeff Webster [SMTP:webstej@MINDSPRING.COM] > Sent: 07 December 1999 11:29 > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: 509 JW osc location > > Graham: > Yes it will erase the osccal value. You need to read this > value before > you erase the part. (Read the "blank" part, and osccal will be in > memory > location 0x3ff). You can put it back by adding this snippet to your > program. > > org 0x3ff ;last memory location > movlw value ;load w with osccal value > > Jeff Webster > Chance favors the prepared mind > > Graham North wrote: > > > > If I erase a 509 JW will the location containing the osc value > also be > > erased? > > > > If so how do I put back the defalt value? > > > > I am using MPLAB and PICSTART Plus programmer. > > > > Thanks > > > > GRAHAM -- I re-ship for small US & overseas businesses, world-wide. (For private individuals at cost; ask.)