2 Jul
2011
2 Jul
'11
7:40 a.m.
Well done!
Thanks Pete,
Have you tried erasing and reprogramming the 27C16s
that didn't quite work
before? I wonder if one or both has a stuck bit, or just wasn't properly
erased. Or maybe they require a slightly different programming voltage to
what you used. Some EPROMs need 25V or 21V, but newer types often need
13V or 12V. And newer types typically want a shorter programming pulse,
or a series of short pulses.
Yes, I've tried a number of them. Unforunately I've only got one type of
27C16, which is NMC27c16Q - 45s (and 35s). Datasheets for the these say 25V
Vpp. They also say tPW should be about 50. However the Willem's default
for 27C16 is 140 us??. The Willem calls the parameter tWP which I assume is
the same thing. Anyway I dropped it down to 50 but it still didn't work.
The default setting for tWC=20 us
Using the default settings for a straight 2716 (tWP= 25 and tWC=50) didn't
work either.
Terry