Problem erasing & re-using GM Proms

[Ludis Langens]

Dave & Irina Eicher wrote:
> 
> Older EPROMs used to have a Vpp pin in addition to the Vcc. The Vpp pin was
> a programming voltage pin, voltage was applied to that pin only during
> programming, not during normal read type operations. Newer chip designs
> simply the interface by incorporating a programming voltage generator
> circuit inside the chip, then the Vcc is the only power the chip needs.

Heading off some confusion: the 27C32B I mentioned wants 6.25 volts on
it's (normally 5 volt) Vcc pin, and 12.75 volts on it's Vpp pin during programming.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/
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