Roger Weichert <rweicher <at> bigpond.net.au> writes:

> I had tried looking around while running with the eprom pulled, but the=20
> waveforms weren't as 'clean' as when I fitted the nop adaptor.

Yes that's the point of the NOP adapter, it removes the questionable glitch=
es.
=20
> I only recently bought an old  Dataman S4 burner off ebay and have used i=
t a=20
> lot. About a hundred chips so far. Surprisingly useful, though finding=20
> blanks of the old chips eg 2716 etc is difficult.

There are sources of old 2716s around but one thing one can do (and what I =
did a
lot) was to retrofit 2732s instead with an adapter and more importantly 283=
2,
the EEPROM version. No more 20 minute waits for UV erasure.
=20
> In fact in searching through my Z80 stuff I came across two 2716's in a b=
ox=20
> with an eprom burner I built myself back when I was studying processors 2=
5=20
> years ago.
>=20
> The Dataman has been handy to make copies of the eproms fitted to boards=
=20
> that come in, even if it is just a file stored on my pc. It's surprising =
how=20
> often people send me a board to repair with no eprom  ...   how am I=20
> supposed to run it and fix it without one???

Well people who work on boards usually have copies of factory EPROMs and al=
so
test EPROMs.

A test EPROM program I used in the past used the NOP trick to exercise the
RAM/ROM address space and a small loop using IN a,(c) and OUT (C),a or such=
 to
exercise the IO port space. This was dangerous with certain attached hardwa=
re
which had to be made safe by removing motor power supplies, fuses etc.

-- Peter


--=20
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