[Coco] Back to the 6809 after 25 years!

[mike delyea]

Welcome back

On Thu, Apr 26, 2012 at 12:51 PM, Juan Castro <jccyc1965 at gmail.com> wrote:

> Hello all, list newbie here. Like Mick Jagger said, please allow me to
> introduce myself.
>
> My name is Juan Carlos Castro. I live in Rio de Janeiro, where, between
> 1984 and 1987, I worked at a now-defunct company that sold a heavily hacked
> (in great part by me) CoCo 2 clone, from 1984 to 1987. Back then, by
> Brazilian law foreign companies didn't have any copyright claim to hardware
> designs or software<
> http://articles.chicagotribune.com/1987-06-28/business/8702170519_1_computer-market-copyright-protection-foreign
> >,
> so we freely copied and patched CB, ECB and DECB. It was fun.
>
> The company created, among other things, an 80-column adapter and a memory
> expansion. They weren't as spiffy as the CoCo3 ones -- The bank switching
> only selected which 32K of the max 256K would be mapped onto 8000-FFEF.
> And the 80-colum card was based on a cheap, common chip typically used in
> dumb terminals. I forget its name. The company developed small business
> software that used those expansions and others. I did the software for
> those two, along with lots of random BASIC enhancements. I vaguely remember
> a better EDIT, some @ SAY GET like routines, and printing the graphics
> screen.
>
> Other things I remember doing is virtualizing the sector read/write
> routines so the CoCo would access a disk in another CoCo, by parallel
> cable. That cable was also used to communicate with POS terminals, the
> CoCo being a concentrator. Small businesses, remember. Oh, and there was a
> whole team of developers making business systems in BASIC! Which were the
> main consumers of my assembly stuff.
>
> The Unravelled books were my lifeline. OK, that, and some chip data sheets.
> The lengths to which I would go to make space in the ROM for my patches
> were truly frightening. Let's just say the boot messages in ECB and DECB
> were greatly shortened to make way for code. I kid you not. Much EPROM
> eraser ozone was smelled.
>
> Ah, yes, there was a hardware hack (not mine, I only did assembly hacks for
> other people's hardware hacks) to make the CoCo use only static RAM. The
> idea was to keep the data by battery on power off. I saw some sorta-working
> prototypes but if I remember right it didn't go anywhere. The company
> abandoned the 6809 line circa 1987 and went PC.
>
> ...and now the nostalgia has finally overcome me and I'm again into 6809
> programming. The almighty Entropy took away my CoCo and my source code,
> sadly, so I'm relearning everything from (almost) scratch, and reduced to
> using an emulator and the CASM assembler. For starters, I'm doing a routine
> to make BASIC use the PMODE 4 graphics screen for text. A hack similar to
> the 80-column one. Screenshots below. (I gotta fix the newlines.)
>
> Cheers all. I wish I could go to Elgin in May, but my overseas travel
> budget is busted for a couple of years at least. :( Have fun.
>
> Juan
>
> [image: http://i.imgur.com/SlQ7Y.jpg]
> [image: http://i.imgur.com/odDTn.jpg]
>
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