> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf
> Of Herbert Graf
> Sent: 31 January 2007 18:33
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE] USB routing and termination
> 
> 
> On Wed, 2007-01-31 at 09:17 -0800, alan smith wrote:
> > I was given a project that was shelved some time ago, and the 
> engineer that was working it is long gone.  No PIC, has a PSoC on 
> it, being used as a USB bridge among other things.  It was routed 
> as just signals, across the board, so no wonder it doesnt work. I 
> assume that it should be routed as diff pair for one thing, but 
> anyone know off the top of thier head what the route length 
> restrictions are?  Also, the design has a 120ohm transformer in 
> line (assume for EMI?) as well as a 27.4ohm resistor in series 
> with the D+/D- lines.  All the designs I've seen just come from 
> the chip direct to to the header for the USB connector. 
It does seem a bit weired especially the transformer

what does the datasheet for the chip in question say?

is this low speed? full speed? high speed?


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