multiple instances of usbjstik

[watlers world]

since it is possible to have Multiple instances of USBUHCI
is it possible to have multiple instances of usbjstik to match?

One other thing...
Are the 1.5Mbit/s of uhci like SATA Mbit/s
SATA 3000Mbit/s =300 MB/s
UHCI 1.5Mbit/s=0.15 Mb/s

[Bret]

It would theoretically be possible to have multiple instances of USBJSTIK, but it's not designed that way. The single driver handles several joysticks, so there shouldn't be a need for multiple instances. There's also no good way for multiple instances to "share" the limited BIOS joystick interface (which only allows for 4 buttons and 4 axes).

There are 8 bits per byte, so 1.5 Mbps = 187.5 kBps. But there is also a lot of overhead associated with USB, and a USB bus can be shared among multiple devices, so the amount of actual data that can be transferred is nowhere near the bus speed. I don't know how efficient SATA is in that respect.

[watlers world]

I had some more time free of late
So I started to examine uhci 1.0 and your drivers again
then as I consider multiple usb joysticks...

I seem to remember...
from back in the 90s (before I even had a computer)

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An old friend who loves a good PC game (first person shooters)
He was the sort of person who would spare no expense on his hobby
and already had the best/fastest hardware and joysticks he could.
Was first telling me how fast and great USB would be(1.0 at the time)
The brag was that it was a Really good High Speed standard.

Then later I was told by him....

A cheap digital 2 button game pad was purchased first
which turned out to be ~ok~ but a bit slow

Experts then told him that he simply had purchased a poor quality controller.

so he got one of the original usb wingman
It turned out to be better than the cheapo... but slower
than his current high end (non usb joystick)

And it made things even slower when you connected
Both cheap and expensive usb controllers at once.

After that He got a newer computer,usb version and a newer wingman
and was happy with them all.

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the details are a bit hazy as...
I really did not care about computers at the time
but I sure remember he was upset about usb 1.0

Does this sound like somthing my memory has dreamed up?
or does that all sound right?

though clearly those must have been primitive drivers
how many joysticks would keep a good report on a 1.0 controller?

[Bret]

What you remember could indeed be his experience. There are so many variables that can affect the speed, though, that cheap vs. expensive isn't really a valid criterion. It's far more complicated than that and is determined by what happens in the hardware and firmware/software. Your friend's early obsession with USB seems to be based on marketing hype, not on how things actually work.

Unlike a standard game port, USB is VERY software intensive, so a faster computer definitely makes a difference. A standard game port is very simple and requires very little either in terms of hardware or software, but is always going to be slow just because of the way it's designed.

With USBJSTIK, it's ALWAYS better to use the BIOS interface (INT 15.84) instead of trying to access I/O port 201h directly, at least if you care about speed. INT 15.84 will return with the data very quickly, while it's impossible for the port 201h virtualization to happen quickly.

[watlers world]

no problems with speed
usbjstiks is quite fast even on an 82371SB
you've designed it to work on all computers

I notice that
"bus-powered hubs may not be connected in series to other bus-powered hubs"

Does this include the 2 built in ports?
or can you have 2 buss-powered hubs on a single uhci controller?

thanks for the info

[Bret]

No, the two built-in ports are called the root hub, which is an integral part of the UHCI host controller. The root hub and all self-powered hubs (ones that you plug into a power source) have enough power to run themselves (usually about 100 mA) and also supply 500 mA to each downstream port. A bus-powered hub draws both the power it needs to run itself (again, usually about 100 mA) and also its downstream ports from the port of the hub it's plugged into (whether it's a root hub, self-powered hub, or bus-powered hub).

You can sometimes get away with connecting multiple bus-powered hub in series, depending on power requirements of the various devices. But, the specifications say you shouldn't do it, and it is just in general a bad idea. Devices tend to lie about their true power requirements, and when a device doesn't have enough power it can do some really strange things.

Also as an FYI, the spec says you should never have more than 5 levels of hubs between any device and the host controller, to make sure the timing parameters remain within tolerance. I've deliberately chosen to not enforce this rule in my drivers, so it's actually possible that you could get away with more than 5 levels of hubs and still have things work OK. I've never tried it myself, though.

[watlers world]

I lack experience with the actual devices


Thanks for the device and programming help