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80386DX ISA single board microcomputer

alexandrugroza.ro

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Re: 80386DX ISA single board microcomputer

#11

Post by timonoko »

flyinglizard wrote: post #7

Awesome project, although I personally can’t identify with putting such effort into reinventing the past instead of making something new. I suspect different people live in different periods. I’ve known people who always dwell on the past, those who are preoccupied with the future and those who are in the present and not overthink too much in either direction.

"Interesting History" is just before your own time (of sentience). I would consider rebuilding 1972 computer a worthy task. But not some 1990 beige box from China.

Re: 80386DX ISA single board microcomputer

#12

Post by pjmlp »

wruza wrote: post #6
ahefner wrote: post #5

Earlier quoted context omitted.

How so? SX was always the crappy version.

I was also confused by this statement and had to refresh my memories. In short, 386sx had 16/24 bus instead of 32, which made it 286 main board compatible. 486sx was simply non-fpu version.

As 386SX owner, it was also the no-FPU version.

Re: 80386DX ISA single board microcomputer

#13

Post by roywashere »

> And there is the original Duke Nukem (DN1, DN2, and DN3) which I always would have liked to have the ability to turn down the volume for. Playing without sound effects was no fun and with sound effects was disturbing for the other people in the house.

Is there a good reason that most XT/AT era computers had no volume control for their PC speaker? I always wondered. My dad's XT had an incredibly loud speaker, I always felt bad playing Accolades Test Drive on it. When I finally bought my own XT I was very happy with the fact the speaker was a little less loud

Re: 80386DX ISA single board microcomputer

#14

Post by hulitu »

DeathArrow wrote: post #9

I wonder, apart from having fun and scratching some nostalgia itches, what are the outcomes of this? Do any of the things learned by doing this project help in working with present day hardware?

You can run Windows 3.1 which has a GUI more advanced than win 10 GUI. But 32 MB RAM ? Is there any Win 3.1 app which can use so much RAM ?

Re: 80386DX ISA single board microcomputer

#15

Post by donio »

pjmlp wrote: post #12
wruza wrote: post #6

Earlier quoted context omitted.

I was also confused by this statement and had to refresh my memories. In short, 386sx had 16/24 bus instead of 32, which made it 286 main board compatible. 486sx was simply non-fpu version.

As 386SX owner, it was also the no-FPU version.

None of the 386 models had on-chip FPU. That came with the 486.

Re: 80386DX ISA single board microcomputer

#17

Post by jtl999 »

anyfoo wrote: post #8
flyinglizard wrote: post #7

Awesome project, although I personally can’t identify with putting such effort into reinventing the past instead of making something new. I suspect different people live in different periods. I’ve known people who always dwell on the past, those who are preoccupied with the future and those who are in the present and not overthink too much in either direction.

A lot can be learned for the present from such projects. Older stuff is usually less integrated, more tolerant to manufacturing by hand (for many reasons, including relatively easy to deal with frequencies, board layout, and required layers), and you have plenty of "reference" implementation and documentation to delve into. It is a very valuable hands-on experience that certainly gives an edge over people who only kn…

I guess the idea is if you're studying EE and related fields: "crawl before you can walk"

Re: 80386DX ISA single board microcomputer

#19

Post by yitchelle »

It is truly amazing that one person can bring up a 386DX board system. It is true that there are tons of docs available, but still to bring everything together and to get it running is truly amazing. The team size at any of the PC OEMs doing a 386DX design when it was the state of the art would be at least 25 engineers and managers, easily.

Congrats to Alexandru for hitting this out of the park.

Re: 80386DX ISA single board microcomputer

#20

Post by anyfoo »

roywashere wrote: post #13

> And there is the original Duke Nukem (DN1, DN2, and DN3) which I always would have liked to have the ability to turn down the volume for. Playing without sound effects was no fun and with sound effects was disturbing for the other people in the house. Is there a good reason that most XT/AT era computers had no volume control for their PC speaker? I always wondered. My dad's XT had an incredibly loud speaker, I alwa…

Somewhat. The internal speaker in the original PC was pretty much just a buzzer that was probably never intended to output anything else other than simple status beeps in office settings.

It does not even have the ability to modulate its amplitude, i.e. its voltage level is either "full on" or "full off" and tones are usually played by doing that, for example, 2000 times a second to get a 2kHz square wave tone. There seem to be some (likely rather PC model specific) tricks to toggle it quickly enough to get some in-between waveforms[1], but overall there are no "volume" levels.

While it's likely not very hard to have a circuit to manually reduce the overall amplitude[2], by the time this really became commonly desirable enough we probably all had sound cards anyway, if we wanted to play anything more prolonged than the system beep on it.

[1] By means of inertia, the mechanical kind or the electromagnetic kind.

[2] Or even in software, but nothing would support that.

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