newbie building a scratch-built computer - test-drb@ccmp.vtda.org

5 Aug 2007

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Subject: Re: newbie building a scratch-built computer
   From: ard at p850ug1.demon.co.uk (Tony Duell)
   Date: Sun, 05 Aug 2007 21:21:07 +0100 (BST)
     To: cctalk at classiccmp.org

[EPROM emulatoros]

  *) Maybe your and my programming strategy
differs; now with SW emulators
 for almost any old CPU being available ona PC, I tend to test my code in 
It does. Remember I don't have anything that will run such an emulator at 
anything like a reasonable speed. 
For test reasons often not a requirement to run at near real speeds.
Sometimes slower is good for testing, most sims can do things even 
a hardware front pannel would envy. Usually I use a spare 486dx/66, 
certainly not lightining fast but enough to test to see if the code
even runs and usually decently fast.  the P1mmx/166 I use for email
and stuff runs Myz80 and Dunfields NS* Horizon (4mhz z80) and 
CUBIX (6809) SIMs all run close to or better than real speeds.
Thats good enough considering the tools they provide as an offset 
if any.

...
 Anyway, I like to write little test programs to run on
the target 
hardware (maybe just outputing a message through the serial port, or 
blinking some LEDs, or...). Just to make sure the target is doing 
something sensbile. 
I prefer to run on hardware too but, there are times when a my 486/75
laptop is at hand and I'm way from my bench so why not?

Allison