USB enabled Mystic?

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What about adding USB support to the 575 based Mystic? That would be pretty nice. Has anyone thought about it? Maybe start by hacking a Keyspan USB->serial adapter?

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dankephoto's picture
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Joined: Dec 20 2003
Posts: 1900
nope, USB requires a PCI Mac

Mystic is nubus based so not possible.

No, you can't work a USB-serial adapter backwards, not even the remotest possibility of that working.

Only way to get USB is to move up to a PCI LB and then it ain't a Mystic no mo', eh?

dan k

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jt
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Joined: Dec 20 2003
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NEVER say: never!

. . . and NEVER tell me something is impossible! I cheat! Evil Block Company

Blast from the past: USB on 68k's, the Endless Quest

jt Smile

p.s. it may be time to start a new USB on 68k project in the hacks forum, I'll bet the available options have come quite a ways since that thread!

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dankephoto's picture
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move along, there's nothing to see here.

OK, it would be nice, but after all these years and no-one has yet demonstrated a single instance of using USB on a pre-PCI computer. This is a topic debated wherever I go and while I appreciate and understand the interest, the plain fact is that it would take a very very considerable effort to make it happen in any practical way. That's why no chipmaker ever made a nubus/or/ADB to USB chip, cost too high for waay too small a return.

Heck, I can use a USB mouse and KB on my IIci, if I use my TiBook to access the IIci with Timbuktu! Sure, put an entire computer between the ADB Mac and the USB devices, that'll work! Practical? LOL, no!

I welcome the event I'm wrong, but in the meantime get on with life and put those energies instead into something worthwhile achievable within our lifetimes.

dan k

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Eudimorphodon's picture
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Joined: Dec 21 2003
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Re: move along, there's nothing to see here.

dankephoto wrote:

Heck, I can use a USB mouse and KB on my IIci, if I use my TiBook to access the IIci with Timbuktu! Sure, put an entire computer between the ADB Mac and the USB devices, that'll work! Practical? LOL, no!

You know, you say that as a joke, but considering how cheap full-fledged powerful computers are these days it's a perfectly valid suggestion, and practical compared to the alternative. Custom software is a lot cheaper then custom hardware these days.

Witness how, for instance, Atari and Commodore enthusiasts who still use actual hardware often use custom cables to allow a PC with a bit of software to emulate the original floppy drives (or hard disks). Economically it makes a lot more sense then fabricating native hard disk controllers for the machines. Similarly, using an entire PC with a bit of softare as a "USB peripheral converter" for a 68K Mac is going to be *cheap* compared to the software development effort and hardware fabrication costs involved in putting together a native controller for those machines.

Of course, eventually one gets to the point where one has to ask themselves whether it's worth using the original hardware at all. The cheapest current motherboards on the market will emulate a 68K Mac at ten times the speed of the original system, so...

Anyway. Progress marches on.

--Peace

jt
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Re: move along, there's nothing to see here.

dankephoto wrote:

Heck, I can use a USB mouse and KB on my IIci, if I use my TiBook to access the IIci with Timbuktu! Sure, put an entire computer between the ADB Mac and the USB devices, that'll work! Practical? LOL, no!

Don't laugh so loud . . . :Smile . . . dr. bob backed off from your position and suggested a simple microcontroller hack. Besides . . . whatcha think all those USB bridge chipsets that AREN'T compatable with 68k Mac I/O happen to be? * CATION - hyperbole ahead * YUP! microcontrollers, just like every other peripheral interface adapter on the planet!

If you look at the posts, i2c - USB bridges were the best bet back at the time, I wouldn't be at all surprised if the CUDA IC weren't a prime candidate as the entry point for that lil hack!

jt Wink

p.s. I think it's time for one of the admins to move this thread to "hacks" or 68k unless, of course, Stuart decides he's interested in this lil' O.T. bit.

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Eudimorphodon's picture
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Re: move along, there's nothing to see here.

jt wrote:

Don't laugh so loud . . . :Smile . . . dr. bob backed off from your position and suggested a simple microcontroller hack. Besides . . . whatcha think all those USB bridge chipsets that AREN'T compatable with 68k Mac I/O happen to be? * CATION - hyperbole ahead * YUP! microcontrollers, just like every other peripheral interface adapter on the planet!

If you look at the posts, i2c - USB bridges were the best bet back at the time, I wouldn't be at all surprised if the CUDA IC weren't a prime candidate as the entry point for that lil hack!

You know, I think what we really have here is a problem with, well, defining the problem. When one says they want "USB on a 68K Mac", does that mean that they want a dedicated controller to drive something trivial like a mouse, or do they want a full O/UCHI-complient USB interface that'll accept any arbitrary USB peripheral? The former could be done "reasonably" with a microcontroller, assuming someone has lots of time on their hands.

(A promising route might be to use something like this:

http://www.gumstix.com/products.html

Admittedly, one has to live with the irony that your mouse converter has a lot more power then your host system, but...)

Doing the latter, creating a fully working general purpose USB controller, is a pipe dream, and it seems pretty pointless to pretend otherwise. The hardware and OS hooks simply *don't* exist in those machines.

--Peace

P.S. Incedentally, you do understand that USB is client-controller based, not peer to peer, right? i2c to USB bridges exist for connecting serial devices to USB. You can't just turn one around and use it as controller. I'd suggest reading this:

http://www.usb.org/developers/docs/usbspec.zip

And getting a real understanding of how USB works before suggesting how "easy" something would be to slap together.

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Joined: Dec 20 2003
Posts: 68
Really simple: ADB to ps/2 Ad

Really simple: ADB to ps/2 Adapter to Ps/2 to USB Adapter...

lol (Wouldn't work)

dankephoto's picture
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Re: move along, there's nothing to see here.

Eudimorphodon puts it nicely:
"You know, I think what we really have here is a problem with, well, defining the problem."

I know a microcontroller could intermediate between a USB device and an ADB Mac, but I think SMA's question is rather specific and pointed:
"What about adding USB support to the 575 based Mystic?"

and the answer has to be no. Sure, we can add the tiny little caveat - yes, USB could be added to a Mystic if one has the knowledge and resources to develop a complete bridge, either in HW or using a programmable microcontroller. However, is that at all realistic?

I think my original answers responded to the original question, not to some engineering challenge. The real world answer has to be no, forget it, move on, do whatever you need to do using something other than USB.

dan k

PS: OTOH, Eudimorphodon also wrote:
"And getting a real understanding of how USB works before suggesting how “easy

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Eudimorphodon's picture
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Re: move along, there's nothing to see here.

dankephoto wrote:

Easy?!? Easy????? LOL, so when did any respectable 'Fritterite stop because something wasn't easy? Laughing out loud

Snicker. Maybe I should of said "possible" rather then easy. I admire the obviously *very hard* work some people do when modifying their computers, but... there really is a line beyond which you're not talking about things which are reasonable for individuals to do. And mounting a full-scale development effort to port OHCI USB hardware and software support to obsolete versions of Macintosh hardware is well past that line.

(Mind the fact that you'd be doing this on an obsolete, often sketchily documented proprietary hardware platform without the support of the manufacturer.)

Perhaps there needs to be a "Daydream" forum where people can describe their fevered visions of what could be without misleading those who are looking for real answers regarding what's actually possible.

--Peace