[ColorForth] Why I'm Here

["Arthur W. Green" <goshawk@xxxxxxx>]

Mr. Ivie wrote:
> My personal gripe about USB is that it seems like Intel did things
> differently just to be different. The stuff USB is doing could be done
> just as easily with something like HDLC which has been available 
> off-the-shelf for decades. Had Intel not used a new whacky bit-stuffing
> algorithm and CRC polynomial for the commands (which are different from
> what USB uses for data, BTW), they wouldn't have had to invent any
> hardware at all; the electrical interface seems to be pretty similar
> to that offered by the antique 26LS32, but I'm no expert.
> 
I wouldn't doubt it.

> But all that aside, bear in mind that USB isn't really a bus. When your
> computer speaks USB, it's talking point-to-point to the USB hub, which
> is then passing the data along to the appropriate device. If all you want
> is a high-speed serial interface to a single device, just plug it right
> into the PC and forget about supporting hubs.
> 
You're right. My mistake. I don't know anything about USB, so I am sort of
talking without any real knowledge of it.

So, I suppose term USB "bus" is a misnomer, even when the machine has isolated
ports (in other words, not joined by a hub) coming off of the motherboard?

The device I look to plug into the USB interface [eventually] is not a USB
device. It's a "standard" serial device, so that was my real concern. Assuming I
"match" the electrical differences of both devices, I'm back to original
question. Can I plug this device in, without any "additional" circuitry and just
read and write raw from the USB ports, much like a standard serial port?

Am I still stuck with the 1ms "granularity" with these ports, or does this go
out the window? I'd imagine I'd have to make my own form of stamping to keep the
information timing accurate since would not using the usual USB stuff, but I
really don't know.

Do I have to setup my own buffer, or does the hardware already have that?

All these are the questions of a USB ignorant, but the answers would be greatly
beneficial to me. Most of the specs don't seem to be particularly helpful with
my questions (or are they?).

> 
> If you're willing to do your own thing, you might take a look at
> IEEE 1355, which is the standardization of the old Transputer
> communication links. See http://www.1355.org/. Being an IEEE standard,
> they want you to pay for a copy of the document. However, they do have
> copies of the data sheets for old chips that implemented the Transputer
> links. Look under "archive".
Thanks for the information. Actually, this is pretty useful, but for the moment,
I am just trying to take advantage of what already existed on the motherboard I
will be using. So, I guess I have to look into that some more, somehow.

Best regards,
-- Art
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