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Date:      Sat, 9 Apr 2005 06:01:18 +0200
From:      Bernd Walter <ticso@cicely12.cicely.de>
To:        Julian Elischer <julian@elischer.org>
Cc:        David Gilbert <dgilbert@dclg.ca>
Subject:   Re: Tricky USB device.
Message-ID:  <20050409040118.GZ96690@cicely12.cicely.de>
In-Reply-To: <42572A96.4090205@elischer.org>
References:  <16982.46075.115518.130213@canoe.dclg.ca> <4256B5EB.9080506@savvis.net> <16982.47024.135663.645297@canoe.dclg.ca> <20050408190514.GS96690@cicely12.cicely.de> <16983.465.572693.73195@canoe.dclg.ca> <20050408233301.GW96690@cicely12.cicely.de> <4257181F.1040904@savvis.net> <42572A96.4090205@elischer.org>

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On Fri, Apr 08, 2005 at 06:06:30PM -0700, Julian Elischer wrote:
> Maksim Yevmenkin wrote:
> >Bernd Walter wrote:
> >>On Fri, Apr 08, 2005 at 06:12:33PM -0400, David Gilbert wrote:
> >>Yes - you must use 1 - there is only one out-endpoint. 0x81 is for
> >>receiving data and endpoint 0 is the mandandory control endpoint. 
> >>Interrupt Endpoints are not variable in size. Both interrupt
> >>endpoints are 8 Bytes, so you must read and write exact 8 Bytes per
> >>transfer - 5 shouldn't work for USB compliant devices.
> >
> 
> the device may accept 5 bytes of data. if it's feeling charitable.
> but you probably should send teh number of bytes suggested by the 
> endpoint descriptor.
> that number is at least guaranteed to work.  Hang on.. I'm trying to 
> remember if the 8 includes the header..

The size is just the payload - I was just wrong, as interrupts
transfers are allowed to be smaller.
However the device should make use of 8 Byte packets or not say 8 Bytes
at all.

> if so then you probably only get 5 bytes of data space.. I need to go 
> back to my USB book.
> 
> From what I saw before, you may need to set the configuration number
> to 1 before it will do anything.
> so you may need to do a setConfiguration(1)

ugen will have done that already, otherwise it wouldn't know about
the devnodes for the interrupt endpoints in the first configuration.

-- 
B.Walter                   BWCT                http://www.bwct.de
bernd@bwct.de                                  info@bwct.de



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