[Gb-ccb] USB interface module

[Martin Shepherd]

On Tue, 20 Jan 2004, John Ford wrote:
> You might look at the usbmod4 product, which has the ability to be
> programmed to do the xilinx download through its FIFO interface
> through an enhancement they call "bit-bang mode".  Very nice!

That looks great.  I hadn't seen this, since the web page that I
mentioned in my previous email, doesn't list this module. In fact it
looks as though I found the wrong web site before, so for anybody else
who is interested, the correct manufacturers web site is actually,

  http://www.ravar.net

and the datasheet for the module that John found, is available there,
at:

 http://www.ravar.net/download/USBMOD4.PDF

> I should point out that there is a discrepancy in the data sheet.  The
> verbiage quotes a rate of "for transferring data to / from a
> peripheral and a host PC at up to 8 Million bits (1 Megabyte) per
> second.", and then says in a different part of the sheet,
> "Send/Receive Data over USB at up to 1 Mb/sec." (note lower-case 'b')

They certainly wouldn't be the only people to get confused by MB vs
Mb. I know that I can never remember which is which.

> I'll confirm with them that it is suitable for the purpose we intend.

That would be great. Thanks.

Assuming that this module does meet our requirements, what are your
preferences wrt getting a fully assembled module and mounting that on
the main CCB PCB, versus getting the individual chips for mounting
directly on the CCB PCB? The assembled module looks pretty compact, so
I would imagine that using this wouldn't use up much more PCB
real-estate than doing a custom layout on the CCB PCB.

Martin