28 Apr
2002
28 Apr
'02
7:20 p.m.
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
There was one big advantage to starting from a home
computer rather than
just a CPU chip. You had a 'base system' that included enough software to
PEEK/POKE bytes to your homebrew add-on for testing.
That alone made life
a lot easier when you wwre starting out.
Tony! This is exactly the point I was making a few months ago about the
ZX81. At that time, you said you'd prefer to start with a Z80 and build up
from there, while I suggested that the ZX81 was a
better starting point for
a homebrew system since the BASIC and video were
built-in.
Care to clarify?
Glen
0/0
29 Apr
29 Apr
12:42 a.m.
Unless you really insisted on using BASIC, there were several free monitors
that required only that you substitute the addresses, and perhaps a couple of
bit masks for what was in place in the serial port driver. With a "real"
monitor you could write loops that were not so slow that your 'scope would
fail to display a consistent waveform because of the infrequency of the
trigger event. If you required a composite video output, and could tolerate
working around the hardware you didn't need, modifying an educational toy like
that might, indeed, have been easier for the inexperienced. A storage scope
or logic analyzer would probably have made working with the BASIC easier,
though.
Dick
----- Original Message -----
From: "Glen Goodwin" <acme_ent(a)bellsouth.net>
To: <classiccmp(a)classiccmp.org>
Sent: Sunday, April 28, 2002 10:20 PM
Subject: Starting point
From: Tony
Duell <ard(a)p850ug1.demon.co.uk>
There was one big advantage to starting from a
home computer rather than
just a CPU chip. You had a 'base system' that included enough software to
PEEK/POKE bytes to your homebrew add-on for
testing. That alone made life
a lot easier when you wwre starting out.
Tony! This is exactly the point I was making a few months ago about the
ZX81. At that time, you said you'd prefer to start with a Z80 and build up
from there, while I suggested that the ZX81 was a better starting point for
a homebrew system since the BASIC and video were built-in.
Care to clarify?
Glen
0/0
3:10 p.m.
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8097
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8098
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3 comments
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participants (3)
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acme_ent＠bellsouth.net -
ard＠p850ug1.demon.co.uk -
edick＠idcomm.com