Y-cable and USB-OTG: mutually exclusive / the four connectivity solutions

Andy Green andy at openmoko.com
Thu May 1 10:07:05 CEST 2008

Hash: SHA1

Somebody in the thread at some point said:

| i agree on all - mini not micro usb, and the switch sounds nice
(though from an

If we play the OTG game we have to use micro USB.  The benefit is we can
source standard charger and cables.  I didn't see any good reason to use
mini USB instead.

| ID point of view sean is mentioning having the back held in by screws so
| changing that switch may be a little hard, but then again... how often
will an
| end user really need jtag?).

OK here are the possibilities I saw

A) Internal JTAG uUSB / external OTG uUSB
B) External JTAG and OTG uUSB x 2
C) External OTG, headphone jack JTAG USB
D) External OTG, magic mode switch to send to FTDI

~                     A                  B  C  D
USB sockets      :   2 (1 internal)     2  1  1
Charge & OTG ok  :   Y (with back off)  Y  N  N
Standard cables  :   Y                  Y  N  Y

"Charge & OTG ok" means you can power and fast charge the thing using
one USB socket with the wall adapter while you use the OTG socket for
USB devices or host connection.

I favour B, A, C, D in that order.

| i definitely think we need to have the usb connector at the bottom of
the case
| - not the side. docking/cradles really would demand this.

I don't really have an opinion about where they go, other than any debug
one needs to be less obvious: we mainly need to settle how many and of what.

- -Andy
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org


More information about the hardware mailing list