> >I'm having trouble erasing 16C64 EPROM parts with my UV eraser lamp --
> >they take way too long to erase (three or four times as long as
> >27xxx EPROMs take).
>
> You will probably find that only the configuration bits (especially the code
> protect bits) are what is taking so long.  uChip has increased the robustness
> of the code protect bits to reduce the possibility of the CP bits erasing
> first thus allowing someone to read out the code from a protected part.

Yes, that sounds right: the last fuse to go in my experiment of three
16C64s was the CP fuse -- it took more than twice as long as the code
itself.  The code took about twice as long to erase as a 27128.

Examining the chip I wonder where the config fuses are.  The EPROM
array is clearly visible, and next to it is a small structure that
*could be* the configuration fuses.  Is this really so, or has uChip
buried the config fuses in the code EPROM array?

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Frank A. Vorstenbosch        +31-(70)-355 5241        falstaff@xs4all.nl