Chris Brown <root(a)tx-rx.org> writes:
> I would be interested in connecting with USB. Can you please ask Keith to
> provide the details?
Keith and I just talked this through. Conceptually, it's easy. In
practice, it's really fiddly, because what you have to play with are 3
small holes in the board on 0.050 inch centers.
I'm going to CC our mailing list on this reply so this becomes more
general knowledge. The question for those seeing this for the first
time, is how to use USB to configure a TeleMini v3.0 board?
Leaving the micro USB connector off is one of the ways we made TeleMini
fit in an 18mm tube. But the main system on chip has USB available
still, so when he laid out the board, Keith brought the required pins
out, thinking it might be helpful in debugging or something, and our
software should know what to do if it sees a TeleMini show up on USB.
On one edge of the board (see attached photo), there are 6 holes in a
row, one of which has a square pad, though you really have to squint at
it to see which pad that is. It's the third pad in from one end, and
has 2 round holes on one side and 3 on the other. The side with two is
what you care about... they are the USB plus and minus data lines. 3
connections will do it, GND / D+ / D-.
To actually connect to these holes, the quickest hack is probably to
take some existing USB A to mini or micro B cable, cut the B connector
off, then carefully strip the outer jacket, strip the conductors, twist
and tin their stranded leads, and just stick them into the appropriate
holes. Note that the usual color code for such cables is black for
ground, red for 5V (avoid like the plague getting that near our
boards!), green and white for the data lines. On the cables we buy for
TeleDongle, et al, green is D+ and white is D-, but sadly not everyone
seems to get that right who sells cheap cables. I've never seen anyone
mess up the red and black wires. Fortunately, if you get the data lines
reversed, it won't hurt anything, it just won't work.
It's going to be a bit of a challenge to keep everything making contact
long enough to talk to the board. You might consider finding some
50-mil pitch header pins to solder the wires to so you have a single
thing you're putting in and out of the holes. Or maybe some micro
grabbers on each wire? If you come up with some great solution, please
let me know.
In any case, once you have the USB port wired up, with a battery and
power switch hooked up to the board it should show up as a USB device on
your computer and you should be able to use altosui to configure it just
like any of our other products.
Have fun!
Regards,
Bdale
