RE: USB working on 823..?

Well, at least with the 832e, you can't.

The 823e was made for Kodak in the dawn of USB, before there was the
standard that we have today. As a result, there is a bug in the host mode of
the chip. Slave works fine though. You'll need another chip to do USB host.

I reserve the right to be wrong.
-Jason



-----Original Message-----
From: navinb [mailto:ppc4@rediffmail.com]
Sent: Thursday, May 16, 2002 9:56 AM
To: linuxppc-embedded@lists.linuxppc.org
Subject: USB working on 823..?



Hello ,

Has anybody got usb working successfully on mpc823.
I am trying hard to get the usb host controller properly
working on 823..
are there any know issue or patches available..?

Best Regards,


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Hihn Jason wrote:

Well, at least with the 832e, you can't.

With the 823e, you _can_ :-)

The 823e was made for Kodak in the dawn of USB,

You are getting your 823 and 823e mixed up.  The original 823 was produced
as you said, and to only support a slave USB interface.  In limited cases,
the 823 could support a host interface, but it was tricky with lots of
software timing issues to solve.

The 823e, and newer 850 (Rev. B) processors have some modifications to
better allow USB host support.  These require some external support (looping
a clock back to the I/O pin) and the downloading of a microcode patch for
properly generating SOF timing.

The 823e has other nice features, like bigger caches and more control over
the LCD DMA.


	-- Dan


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