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:     kdowsett@rpms.ac.uk
     Phone:     +44-181-383-3723
Snail mail:     MRC Cyclotron Unit, Hammersmith Hospital, London W12 0NN
       Fax:     +44-181-383-2029