Re: [uCsimm] Using two or mor uCsimms together??

From: Greg KH (
Date: Mon Feb 07 2000 - 22:06:16 EST

On Mon, Feb 07, 2000 at 06:54:33PM -0500, Paul Haas wrote:
> Danger USB digression ahead:
> I expect I'll buy something once someone gets a USB master node working
> under uClinux and more USB peripherals become available. Hmmm, must do
> more research before starting these posts. Looks like I want a
> or something
> like it. First I want Microchip to start volume production on the PICs
> with USB built in. I know PIC assembly code, so I'm waiting for the PIC
> for my peripherals.

That might be a long time :)

Seriously, a USB host controller takes up a LOT of processing power and
bandwidth (PCI is usually required). There are a few host controllers
that do not require PCI (if you're interested I can dig up the
information I have around here somewhere), but they will most likely not
have kernel support, unless you create it yourself.

The current USB code in the 2.3.x series of kernels is pretty tied to
that kernel series. There does exist a back port of it to 2.2.14, but it
isn't perfect (parallel port driver does not work for one).

So if it would ever work with the 2.0.38 version (current baseline of
the uClinux code) is a big guess.

Now if you want the uClinux device to be a USB device, that's another

Cypress has a dirt cheap USB device controller that uses a small
assembly language, not unlike the PIC assembly, small but useful.

If you want more information about Linux on USB, check out There is also a good mailing list for it.

greg k-h

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