Re: a USB for the Apple II smoke test

[The Wizard of Oz <wizard@emeraldcity.gov>]

On Thu, 28 Jul 2005 11:09:11 -0700, Michael J. Mahon wrote:

> The Wizard of Oz wrote:
>> On Wed, 27 Jul 2005 09:47:49 -0700, pilgrimer wrote:
>> 
>> <snip>
>> 
>>>I wonder,
>>>could it be the baud rate on the SSC?  could it be something else? could
>>>it be God never  intended this sort of thing?  Do I really wanna take
>>>this one any further?  Not really, but it was interesting.
>> 
>> 
>> 	I think you may be on to something. I seem to recall the early days of
>> the mouse on the PC there used to be problems with baud rates. As I recall
>> anything above 9600 was fine. It might be cool to see the GS with two
>> mice. Since the PC mice are serial devices (the "S" in USB) I see no
>> reason why it wouldn't work in theory. Perhaps the problem with the SSC
>> could be related to it allowing one connection instead of the three
>> available on the backplate. Since there were mice available which didn't
>> use the ADB connector, it seems logical there would be drivers for them in
>> GSOS.
> 
> Actually, USB has about as much in common with RS-232 as a
> giraffe has with a grapefruit.

	Bad analogy. A better one would be like what a bison has to do with a
cow. The hardware protocols can't be a lot different. After all there is a
direct path from RS-232 to USB. I bought a couple of RS-232 to RS-232-C
(25 pin to 9 pin) adaptors. Friends have bought RS-232-C to USB adaptors.
None of these adaptors required circuitry. It was all a matter of wiring.

> The fact that it delivered power without burning anything
> out is miracle enough.  That it pulsed a data line randomly
> to produce the illusion of data is just luck.

	You have two points here. I agree with the first. Just because the plugs
match does not mean the pins do the same thing. Power to the wrong
component could release the magic smoke. It WAS really good luck.

	Your second point I half agree with. The more I think about it the more I
think you may be correct about the pin producing random data. It would
explain the crash. At the same time, if he went through the path I
outlined earlier then he probably wouldn't have had that problem. Since
adaptors are being sold then the hardware should be compatible. Since
there are serial mice for older Apples and the software appears to exist
in GSOS (backwards compatibility) then a USB mouse *should* work if
properly connected. All he would have to do would be to match the data
format and baud rate.

	I still think he is on to something. For a couple of bucks he could
satisfy his curiosity. It's not as if he won't find another use for the
adaptors. He probably has them already.

> -michael

				Later
				Mike