Post by thread:Pic eraser (Project?]

Hi Having followed the thread about JW erasing and program protect bit erasing, I wonder if someone out there would like to spoil us with a JW reader while erasing is taking place. Maybe a 16C84 could be placed on a pc board with a socket for JW eg. 12C508/9 and constantly read the part untill is is blank. Then beep or turn the UV off ? How about a project challenge ??? Kind regards Cassie

Hi Cassie, You wrote: >Having followed the thread about JW erasing and program protect bit >erasing, I wonder if someone out there would like to spoil us with a >JW reader while erasing is taking place. Maybe a 16C84 could be >placed on a pc board with a socket for JW eg. 12C508/9 and constantly >read the part untill is is blank. Then beep or turn the UV off ? > >How about a project challenge ??? The problem with this method is you are "just" erasing the other device. When the UV light is turned off, the bits may retain just enough charge to show up as a "0" (programmed) in some circumstances). With a bit of experimentation, you should be able to figure out what amount of time is proper for erasing different PICs (they're not all the same). Sorry, it would be an interesting project, but I don't know if I could trust the output, myke "I was well aware that the processes of puberty are often fatal to psychic power." - Sir Arthur Conan Doyle

At 09:54 AM 11/26/97 -0500, you wrote: >Hi Cassie, > >You wrote: >>Maybe a 16C84 could be >>placed on a pc board with a socket for JW eg. 12C508/9 and constantly >>read the part untill is is blank. Then beep or turn the UV off ? >> > >The problem with this method is you are "just" erasing the other device. >When the UV light is turned off, the bits may retain just enough charge to >show up as a "0" (programmed) in some circumstances). > >With a bit of experimentation, you should be able to figure out what amount >of time is proper for erasing different PICs (they're not all the same). > >Sorry, it would be an interesting project, but I don't know if I could trust >the output, I guess you would want to check the erasure at V(min) and perhaps double the time. Sounds fairly straightforward. (famous last words :-) Component list: 12C508 1 Transistor (to switch MCLR) Two resistors Power supply (5 & 12 volt) Solid state relay (or other means of switching lamp on) Pushbutton switch The software starts a 6 bit counter when the erasure starts, and checks the first 64 bytes. When these are all blank it starts reverses the counter and when it reaches zero, turns the lamp off. You could probably steal the code to read the EEPROM from one of the projects to make a 16C84 based programmer. Anyone fancy making one? Keith. Keith Dowsett "Constants aren't, variables won't" E-mail: spam_OUTkdowsettTakeThisOuTrpms.ac.uk Phone: +44-181-383-3723 Snail mail: MRC Cyclotron Unit, Hammersmith Hospital, London W12 0NN Fax: +44-181-383-2029

Interesting ! I would love to see the Payson / Kunz (Read Minimal) soulition ! Maybe there is sufficent space in a '53 or '508 to control a toaster at the same time or an intelegent remote control for all ocassions . If it wont fit they will probably make it............. Cheers Steve..... I might consider this myself as current UV box is RUBBISH (no timer cutout or human protection) Its left behind filing cabenet to shine at cieling and chips are placed on top of tube by hand .............

Wouldn't the UV cause such a photo electric effect that one would have to keep shutting down the light source to test for actual erasure? I suspect that one would get false readings trying to zap and read at the same time. Martin McCormick WB5AGZ Stillwater, OK 36.7N97.4W OSU Center for Computing and Information Services Data Communications Group

Martin McCormick wrote: > > Wouldn't the UV cause such a photo electric effect that one would > have to keep shutting down the light source to test for actual erasure? > I suspect that one would get false readings trying to zap and read at the > same time. Whatever you guy do, bear in mind that the UV rays will lay down plenty of static on any isolated object (- charge). Be sure to have pull downs on all the pins. -- Friendly Regards Tjaart van der Walt .....tjaartKILLspam@spam@wasp.co.za _____________________________________________________________ | WASP International http://www.wasp.co.za/~tjaart/index.html | | R&D Engineer : GSM peripheral services development | | Vehicle tracking | Telemetry systems | GSM data transfer | | Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8973 | | WGS-84 : 26010.52'S 28006.19'E | |_____________________________________________________________|