Re: cheap PC's

At 02:36 PM 7/8/97 -0700, you wrote:
>
>With all this talk about PC's, I broke down and bought one
>(with my teeth clenched, since i'm a senior engr at Apple)
>Used 386/486's are incredibly cheap in the Bay Area! I just
>found a surplus place that had used mini-towers with everything
>but the floppy/hd for $25 !
>
>Guess everybody must be dumping them to get P-whatevers...
>I haven't pulled it all apart yet, but it looked like it
>had either 1 or 4megs of memory in it.
>
>So, how do you do embedded systems with these things? I
>assume if you were going to use it for a sound board in
>a game you wouldn't boot DOS on it..

Al?? You bought a PC???

Wow. Must be one of those End of the Millennium things...

So are you going to write 80x86 code?? *snicker*

---
Most of my jobs have been embedding PC's in one thing or another.
I have some really cool code for booting into a ROM/RAM card.  You have the
choice of making the ROM/RAM look like a floppy or hard disk.
There's a huge difference in price when it comes to buying a ROM card for
the PC backplane.  All the cards consist of are a bunch of sockets, and 5 or
so pieces of glue logic, so I don't know what the deal is. But I've seen
cards with the same capabilities sell for as little as $75 with 512k of
installed RAM/ROM to $399 with no installed memory -- geeze!
Most of the cards come with there own drivers that make the ROM/RAM drive
look like a floppy.
If you buy a Sea Level card (one of the expensive ones) you'll be referred
to AnnaSoft for the driver where you'd end up with a version of my code.
Since development software for DOS is so easy to find (any
compiler/assembler), every place I've worked that needed to boot into a
embedded PC ended up just booting into DOS or a DOS clone.
There are other operating systems that allow booting into ROM (the drivers I
wrote would allow you to boot into any operating system they hook in at the
BIOS level). Most of the other OS's take up a bit more ROM space, since the
OS's are usually much nicer than DOS.
For a Sound card, the drivers are already written for DOS, it's probably the
way to go...
---
If the sound board driver code could be kept small enough it could be stuck
into the ROM socket of an old VGA (EGA) card.  These BIOSes were usually
around 64k. Using DOS 3.1 you can get the needed DOS files down to less than
30k, better yet there are DOS clones (General Software, DataLite) that can
run DOS clone software in as little as 5k.
That leaves around 50k for the sound card software.  You'll have to use a
sound card that doesn't require TSR's to run.  This also requires the sounds
to be emulated since there's very little room for wave files, though wave
files could be downloaded into the sound card's memory on power up.
Whatever, $75 is not bad for a fully function RAM/ROM card that would allow
us to have access to .WAV files.
Gravis supplies such nice documentation for their wavetable sound cards,
that these would *have* to be the card of choice.  They supply example code
to drive these cards directly, and since you can download into them your own
samples, they should be able to sound like any 80's game sound card.  16bit
samples at up to 48khz sample rate should *easily* do justice to even the
Sega Speech cards.
All that would be needed for this approach to work would be the game-to-PC
interface. Probably done with a PIC on the game side and a serial port on
the PC side (or maybe the keyboard port, since all PC's have one of these).
And of course a bunch of software to run the thing.
I don't know, so far this sounds like the most available solution to the
universal sound board problems.
-Zonn
(Hell, if I could get out as much code as I do e-mail, I'd be done with this
project I'm working on here at work.)