Re: [ECOS] AT91 USB driver

[Frank Pagliughi <fpagliughi at mindspring dot com>]

Hello Gábor,

I looked through the Atmel summary and datasheets, and every place it's 
listed says that EP0 has a max size of 64 bytes. What value are you 
using for the "Max Packet Size" in the device descriptor?  If the driver 
is expecting 64, but the device descriptor tells the host to send 8 at a 
time, some packets will fly back and forth but it won't enumerate.  I've 
made that mistake before with other USB chips.

Frank


Gábor Török wrote:
> Hi!
>
> I'm testing the driver, but I did some modifications, because Atmel
> datasheet says that before any other registers are written, the pullup
> must be enabled. But the only consequence is some extra USB resets, so
> I think that shouldn't rendered the USB unusable.
> I included the extra endpoints in the USB driver, so they get disabled
> correctly.
>
> One stange thing was, that the Atmel datasheet said fo AT91SAM7SE,
> that endpoint 0 (main control endpoint) FIFO is 64 bytes long, but in
> any other devices it is 8 bytes long. I have written 64 bytes in the
> USB driver for FIFO size. I was struggling to get driver working for
> some days. The good thing was, that I found other bugs and partly
> corrected that pullup thing at initialization. Today I had the idea to
> reduce the FIFO size for EP0 to 8 bytes, and it worked. I will have a
> look into the USB specification and the code to see if it is an error
> in the Atmel datasheet, or is it a bug in the A91 USB driver or is it
> a problem with my computer.
>
> It works with SAM7SE, the original worked with SAM7 (this one should
> also), and it should work with SAM7X and SAM7XC.
>
> Until then, I commit it to my SVN and later today I will create a
> public read access to allow testing. When it is well tested, I will
> send the patches.
>
> Gábor Török
>
>
> On Sat, Oct 4, 2008 at 10:39 PM, Frank Pagliughi wrote:
>   
> > Gábor Török wrote:
> >     
> > > Hi!
> > >
> > > Have anybody tried the AT91 USB driver with other controllers than the
> > > AT91SAM7S (I only tried with this)? I would like to use it for the
> > > AT91SAM7SE, and after a quick compsrison between the USB registers of
> > > the two chips, I noticed no major differences. The only thing was,
> > > that the SAM7SE has more endpoints and the pullup is integrated, but
> > > all the register and bit definitions are the same (except the bit
> > > controlling the pullup and the registers of the extra endpoints).
> > >
> > > Gábor
> > >
> > >
> > >       
> > I haven't tried it with anything other then the 7S, but if you're going to
> > try it with the 7SE, get the latest CSV sources. There have been a few bug
> > fixes to the driver in the last month or so. Let me know how it turns out -
> > or if you have any problems. I've been looking at that driver recently.
> >
> > - Frank Pagliughi
> >
> >     
>
>   

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