Caisson wrote: > > > Van: John Payson > > Aan: PICLIST@MITVMA.MIT.EDU > > Onderwerp: Re: [SOT] Copy Protection; Reverse engineering vs Theft > > Datum: maandag 3 mei 1999 18:37 > > > > Although I don't know the specifics of the PICs' "factory test" area, I > > would suspect that there's at least one bit in there that Microchip could > > burn on OTP's and leave blank on UV devices. If Microchip were to do > this > > and document it, it would allow programming devices to avoid destroying > > window parts (when burning older PICmicro OTP's, it would be necessary to > > override the feature, but that shouldn't be a problem). > > Something TOTALLY different: We've got fusable Code-protect bits. That > will dis-allow the code to be read. Why can't they introduce a > "Code-protect disable bit" ? It would enable JW-part users to disable the > Code-protect bit, thus NOT keeping them on their toes when programming such > a part. > > Greetz, > Rudy Wieser IIRC the die for a /JW part is *identical* to that for an OTP part, the only difference being that Quartz window. John's idea might be easier to get Microchip to implement, as it wouldn't require a silicon change, just a test procedure change, which Microchip might be far more agreeable to than changing their silicon so us developers won't have to buy more pricey /JW parts... I imagine the OTP parts make up most of their sales, after all. Thought that occurs to me is that Microchip could burn this bit on ALL devices - /JW or not - in a UV erasable area, and then require that you erase the /JW device before first use, at which point you can tell (once that bit erased) whether you have a JW or a OTP part. (Flash parts could be confusing in this situation, except the part NUMBER tells you they're flash parts, rather clearly ) Mark