TRS-80 Model I info (RE: MSX, TRS-80, Colour Genie, etc.)

From: Allison J Parent <allisonp_at_world.std.com>
Date: Thu Jun 26 09:22:19 1997

> Level I BASIC was _NOT_ a Microsoft BASIC. It was a fairly straight
> rendition of Tiny BASIC. Unless I've been lied to for many years. The
> Tiny BASIC published in Interface Age did have floating point, though not
> much precision.

You were lied to. ;-) I have the IA articles for TB and TBX along with DDJ
and BYTE. tiny basic was integer. There were several small basics that fit
in 4k that were not like L1 (different mix of capability) or were MS 4k
clones. Technically it was MS4k. I'd used the altair version and the TRS80
and they were Identical!
 
> The keybounce was a bug in the hardware. Mine always came back when I
> turned the keyboard upside down and dumped out a few months worth of
> cigarette ashes. A week later the problem would go away. (Proof that I
> didn't grow up in a clean-room computer environment -- I was 23 and out
> of the USAF when I got that Mod I in '78).

Wrong. I was doing systems design for a terminal company while at RS(i was
not in sales). That terminal company used the exact same keyboard.
Switches bounce, debounce is simple you detect closure wait a few MS and
verify closure if the verify fails the switc is open. The 4k basic didn't
wait long enough but, beniding the contacts to change their dynamics was
often enough. The verification if this is I clocked off a pulse gen and
at 1.15mhz the bounce would go away! The delay rountine was in software
so slowing the cpu was enough to make the dely longer and it would behave.
some of the speed mods made it worsse unless LII was in there.

I still have my trs80 hackboard (much modified and mangled) that I used to
test various and sundry ideas.

Of course when Tandy has launched the trs80 I'd had my altair up and running
for some time with a TTY, ct1024 (64x16 upper only) and PR40 printer for a
while.

Allison
Received on Thu Jun 26 1997 - 09:22:19 BST