+++ David Bisset [04-12-06 15:12 -0000]:
> >> I made a cable with a A-type usb connector on it to plug into J16 and
> J15. >>I put a scope on the lines on J16 and find no +5 volts, although
> I find it >>on J15.
>
> >Hmm -there may be some number confusion here. Looking at the
> >top_compnents.pdf layout diag then the 3 USB connectors on the top
> are:
> >J15, J7, J16 (closest to J1 - serial/Jtag)
>
> >This is different to the numbering on the clickable image map pic of
> the
> >board on balloonboard.org/hardware/205/index.html (which numbers them
> >J20,J18,J19 (which are the equivalent duplicate sockets)
>
> The USB-on-Molex sockets which are fitted on the top layer of the
> Balloon board are (Left to right and down):
> J16 - Host Port B
> J7 - SA Client port
> J15 - Host Port A
OK - website updated to reflect this. Tell me if anyone finds any old,
incorrect, naming.
> >In fact I can't find J20,18 and 19 at all on the layout files - steve -
> >where are they supposed to be - do they in fact exist?
> >If someone (steve/dave?) can tell me which doc is correct, I'll try and
>
> >make sure they all match up.
>
> Yes they exist as plate through hole clusters on the bottom edge (Samtec
> edge) of the board, I'm not sure but I assume the hole patterns match
> standard sockets, I've never tried to use these and I'm not sure how
> they would be affected by the fitting of the Samtec, I suspect care
> would be needed with the pins that poke through the board, they may even
> be mutually exclusive.
Ah - yes I see them now. OK. I'll add that to the website. If they are
inteded to go on the back then they are definately mutually exclusive with
the samtec.
Actually - I see two set of holes. which are J19 and J20. I still can't find
J18.
> >OK - yes, I am only seeing +5V on the two outer conectors - J15 and
> J16, >but not he middle (slave) one - J7. That appears to be correct
> from the
> >circuit diagram, and makes sense - slave devices (can) take power from
> the >host.
>
> Yes Hosts have to supply power, but you wouldn't want the balloon to
> power itself of the USB port would you :-) Well there's an idea...
> (Steve note the :-))
One thing I did notice looking into this is that the only reason the slave
connector needs 5V to work is the pullup on one of the data-lines. Does
this need to be 5V because that's the USB spec? It just seems that on a 3V
only board you could still use the USB slave stuff if 3V signalling on this
data line would actually work, which might be handy. I imagine this is in
the 'might work but would be out of spec' area?
If this could work, then the option to link this pullup to 3V instead of 5V
with a link might be worth including?
Wookey
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