View Single Post
Old 09-09-2009, 01:21 AM   #13
Kent Walters
Connoisseur
Kent Walters has learned how to buy an e-book online
 
Kent Walters's Avatar
 
Posts: 79
Karma: 92
Join Date: Sep 2009
Location: Northern California, USA
Device: iRex DR1000S, Astak EZreader (Hanlin V3)
Dear scotsman,

Aha! This is what I was talking about when I complained about companies not using the same terminology in the same way regarding usb. iRex does not call the mini USB port on the DR an OTG port--The USB port on the DR is not an OTG port (because the device is portable, and contains a USB port, does not make it an OTG device), according to usb.org:

USB embedded hosts and multiple recepticals.pdf found at http://www.usb.org/developers/docs/EH_MR_rev1.pdf

“3.4 On-The-Go Device
An On-The-Go device contains a single Mini-AB recepticle that will function either as a host or a peripheral. An OTG device defaults to acting as host when a Mini-A plug is inserted, and defaults to acting as peripheral when a Mini-B plug is inserted. The Host Negotiatition Protocol (HNP) allows these roles to be changed.” (Italics added)

The DR does not contain a mini AB recepticle; it is a mini B, and while a hacker could easily configure it to function as a mini AB (assuming that it is wired to the Freescale OTG port), I consider that to be a bad idea, for several reasons (unless you want to know, I’ll spare you the details)--one is the HNP. The spec also says that an OTG device may not contain multiple USB ports, and iRex has included two, even if they won’t tell us where the other one is.

Before I first contacted iRex regarding the DR’s USB, I connected a flash drive; I tried using adapters, wires, and even a powered hub, in every way I could imagine. You are correct in that the DR does not power the port, but applying power to the port will, I think, run us headlong into the Lithium Ion Polymer battery’s power management/charging circutry, and confuse the logic of the DR. (I doubt that Freescale includes charging circutry on their chip; too many variables. Power management and charging for Li-Ion-Poly batteries is very different than other battery types, and has very stringent requirements (see: http://www.batteryspace.com for more info), and Freescale’s chips are used in all manner of devices, with all kinds of power supplies.)

For these and other reasons, I think finding the USB port in the Function Extension Slot is the way to go, someone can make adapter cables for those who are unable to, or unsure of their abilities, I will post a how-to as soon as we figure it out. It will only require the female end of a standard A type USB extension cable and the 20 pin plug mentioned earlier in the thread.

Man! I thought you were the software guy! I haven’t played with Linux since the Berkely Distro (15+ years ago, SCO before that), and I haven’t really done any programming for the last 10 years; I sure ain’t the guy! I did consider installing the iRex developer package on my Mac, but, frankly, with my rusted-out skills, the idea of running a virtual machine inside of a virtual machine is a little daunting--I’m hoping someone will compile a Freescale VM for BSD (found underneath Apple’s OSX), so I could run native. Sorry. (I always look for Mac binaries--failing that, I do without.) I’m prety good with hardware.

Still waiting for my package from China--that will answer a lot of questions.

Take it easy,
Kent Walters
Kent Walters is offline   Reply With Quote