No - this was a silicon bug which caused the USB engine to send 4 spurious
bytes over the interface (causing repeated bus resets). It only happenned
when there were delays between actions on the bus. I am not sure if
Microchip ever admitted this in an errata as their C code worked fine. Check
the Microchip forums for details - several of us had proof of this issue and
raised support tickets.


Robin Abbott
Forest Electronics - Home of WIZ-C ANSI C Compiler for PIC's with RAD Front
end
robin.abbott@fored.co.uk
www.fored.co.uk 
 

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
Dario Greggio
Sent: 25 October 2007 15:29
To: Microcontroller discussion list - Public.
Subject: Re: [PIC] USB PIC related Links

Xiaofan Chen wrote:

>>I converted Microchip's CDC code into a drag and drop component for 
>>our own compiler (WIZ-C), which wasn't too bad a task - except that 
>>the silicon has a bug which meant that spurious bytes are inserted in 
>>transmitted packets unless the timing relationships are exactly correct.
> 
> Which silicon bug are you referring to? I've collected a list of 
> potential firmware frameworks bugs in the Microchip forum thread.
> http://forum.microchip.com/tm.aspx?m=275422

Hi Xiaofan,
I guess he refers to the USART bug, which used to affect some 18F devices
(24 maybe as well): upon fast back-to-back transmission, a spurious byte may
get inserted in the outgoing stream.

--
Ciao, Dario
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