Re: [Balloon] Trying to get a loon with USB host working

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Author: Chris Jones
To: balloon
Subject: Re: [Balloon] Trying to get a loon with USB host working
On 25/10/2011 10:30, Wookey wrote:
>>> I also discovered that you can't use USB host on older loon with the
>>> breakout boards - you have to use a CUED board. Wired up wrong
>>> port/pins I guess.
> Even with a modern 3.32 board there was no power on USB host connector
> suggesting that something softwary needs to hapen to get that turned
> on. But I'm not sure what.
> ...
> Slave works OK on the breakout board, but host does nothing. Haven't
> yet worked out why - will come back to that. Interestingly if you plug
> in both breakout board (via pinko) and CUED board (via J11) then only
> the slave on the CUED board works. Anyone know why that is - shouldn't
> either connector work?

For USB host to work, USB_HOST_PWR has to be connected, otherwise your
USB device doesn't get any power. Even if it's self-powered, it needs
this signal in order to notice that it's been connected to a host.

On a 3v32 board, which I think you're talking about, this signal is
simply not present on the Pinko connector J13 (30-way, top of board). So
the host connector on the breakout board won't work. On a CUED board,
which uses the comms connector J11 (24-way, bottom of board) it will
work, because USB_HOST_PWR is available on this connector.

Only 3v33 boards have all the right signals on Pinko J13 for USB host to
work with the breakout board.

I hope this helps,
Chris Jones -
Martin-Jones Technology Ltd c/o Element Energy Ltd
Twenty Station Road, Cambridge, CB1 2JD, UK
Phone +44 (0) 1223 655611 Fax +44 (0) 870 112 3908