[Milkymist-devel] M1r4 review: USB (was Re: Ask for reviews on M1R4 draft (was Re: M1R4 draft schematics))

[Werner Almesberger]

In USB, I only found one piece I'm not sure about: the internal connector
J24.

- considering [1] (figure 10 on page 14), shouldn't we mark pin 9
  as NC ?

- pin 9 and 10 are marked as USB shield. The above reference has a
  completely different idea about it (overcurrent). Shouldn't we
  NC it too, and leave shielding aside ?

  If you can find one of those little passive commercially available
  header to USB A boards (to plug on the mainboard of a PC), perhaps
  you could check where they connect the shield.

- if we decide to keep shield on J24, wouldn't it be better to
  ground it separately it from the external shields ?

[1] http://www.usb.org/developers/whitepapers/power_delivery_motherboards.pdf
    (available in the bookshelf as "usbpwr")

You were looking for a header that already comes polarized. I think
this one may fit:

http://search.digikey.com/us/en/products/TSW-105-26-H-D-009/TSW-105-26-H-D-009-ND/2685930

Non-stock, but only takes one week. Oh, and it's heavy metal ;-)

- Werner