Right - I understand now... Sometimes it's better to just get on with it. Rabbit holes to dead ends don= 't help a project! Good luck. Stephen -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of= andrew kelley Sent: Tuesday, 20 February 2018 2:05 PM To: Microcontroller discussion list - Public. Subject: Re: [EE]: ancient tc97208/tc97209 datasheet Correct. But if I can write 0s to it (which I can't) proves something in th= is code isn't right. I can't erase it either. If it was otp, I could at lea= st 0 out the chip and not be able to erase.. Well, I guess I'll just end up modifying the boards and repotting them sinc= e absolutely no one has a DS on it. Nothing on Google for a ds, found some = code but it doesn't work. This was my last try. Thanks all. Andrew On Sunday, February 18, 2018, wrote: > > "(But then I ought to be able to program it blank it out to all 0's=20 > and finish it off & just not erase )" > > Hi Andrew - not sure exactly what you mean here but "blank" NV memory=20 > generally means all 1's. If you "blank" it by writing 0's to it you=20 > probably won't be able to program it. Erasing will usually (always?)=20 > set the memory to all 1's. > > Stephen > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive=20 > View/change your membership options at=20 > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .