My reservations about enabling Host on the Dr's mini B port are gone, with some reservations/cautions that I'll explain later (some will find it boring
).
On the DR's board,
all 5 pins to the USB socket are wired. According to the On The Go Supplement (OTG) to the USB spec., pin 4 of a mini B port is not used. The only reason I can think of for iRex to have wired all 5 pins is that iRex
intended the DR to be an On The Go device, and decided not to, and just substituted a Mini B socket for the OTG Mini AB socket (and we must bear in mind that
they may have had a good reason for doing this).
I
suspect that if an adapter cable that connects pin 4 to pin 5 is used (don't do this) to connect a B device (like a thumb drive) that the DR will power the device and respond with an error message (like "Device not recognized").
If that happens, then the DR's port,
for sure, is Host capable, and the 'hardware limitation' iRex spoke of is only the physical socket itself. If it powers the device but doesn't respond, we may have further problems in firmware. If it does
nothing, we are right back here.
My plan is to wire a Mini AB socket to a mini B plug, with all 5 pins wired straight thru (this is illegal, according to the USB spec--see the warning below). I'm having trouble finding a suitable cable, but will visit The Robot Store this weekend, with my hopes. Failing there, I will wire it with two lengths of USB cable instead of one.
I'm hoping to do this weekend, but things keep happening... I'll post back with results. I hope everyone keeps in mind that I have a spare (broken screen) DR to test/hack/destroy.
WARNINGS: The main reason for the different USB connectors is to prevent damaging equipment; if a Host port is connected to a Host port, one or both devices may be damaged (and Murphy's Law applies). If you make a cable like the one that I said, 'don't do this,' PAINT IT RED, and NEVER use it to connect your DR (or anything else) to your computer or charger. This is the cause of my reluctance to using this port on the DR.
A cable like the one I'm going to make will keep everything safe, as long as it is used with USB 'legal' cables and devices. If anyone has any questions, please ask.
BTW, scotsman, could you tell me where to find the Freescale spec? I couldn't find it.
I hope you get some help on the software end
.
Magic Is afoot,
Kent