BruceL: No, no. No personal attacks intended. It's not you, it's me. Let's just be friends, OK?
Oooh so much love. Can I be friends too?
(I've been reading the runaway "Did Your N900 Ship Today?" thread and started getting a little bit silly myself...)
I just had to say something, does anybody except the USB Consortium know WHY they need to have USB-OTG and for what type of devices do they actually intend USB-OTG? If the N900 doesn't fit to the type of device then its alright, else we could partially blame Nokia for false marketing or not knowing what users want. This thread is getting so big, somebody please resolve this or just freeze it.
Furthermore, the spec says it is not allowed to support both powering via microUSB as well as host mode. This is limited on hardware layer.
Did you mean "charging" and not "powering?" Regardless, this statement is untrue even if I don't understand what you're trying to say. As an example, please read section "6. Accessory Charger Adapter" of "Battery Charging Specification, Revision 1.1." Here's a diagram of an OTG device acting as host while being charged:
Regardless, this statement is untrue even if I don't understand what you're trying to say. As an example, please read section "6. Accessory Charger Adapter" of "Battery Charging Specification, Revision 1.1." Here's a diagram of an OTG device acting as host while being charged:
Please refer to your source next time you quote from one.
Your example is the only exception I'm aware of.
MicroUSB revision says a USB OTG device may only have 1 MicroUSB connector which must be MicroUSB AB type.
Nokia N900 has MicroUSB type B which may only use EH mode.
If Nokia N900 had MicroUSB type AB it'd not be allowed to be used for charging and host mode using its same port without an accessory such as the one you state. In that case, one might as well carry a Nokia adapter for charging.
Please refer to your source next time you quote from one.
Sorry, thanks.
Originally Posted by
MicroUSB revision says a USB OTG device may only have 1 MicroUSB connector which must be MicroUSB AB type.
Nokia N900 has MicroUSB type B which may only use EH mode.
If Nokia N900 had MicroUSB type AB it'd not be allowed to be used for charging and host mode using its same port without an accessory such as the one you state. In that case, one might as well carry a Nokia adapter for charging.
If you're saying that the USB specs seem too brittle, I agree. Maybe backwards compatibility is causing some problems. That would be a bummer, because I like USB and I like backwards compatibility.
There is a possibility to add USB host to the n900.
This might sound weird, but we'll need a seccond device... an access point, which also runs Linux, and has a USB (host) port...
I did something similar a few months ago (on another device)
I've submited a few ideas to the PUSH program, and If I get lucky enough to be selected and get a n900 (or a discount), I'll try and implement a virtual usb port for the n900.
This way, you can connect a usb device to a specific (but cheap) USB enabled access point, whose "host port" is then "forwarded" to the n900, via WIFI.
This might sound weird, but we'll need a seccond device... an access point, which also runs Linux, and has a USB (host) port...
[...]
This way, you can connect a usb device to a specific (but cheap) USB enabled access point, whose "host port" is then "forwarded" to the n900, via WIFI.
Thanks, but both ideas are already discussed in the thread, and various solutions are linked to. Each solution has their side effects.
For example, in the first example the 'second device which runs Linux' (does not _have_ to be Linux btw) is the actual 'client' because its the 'host'; the N900 is assumed a dumb device (EH). Can be solved by issuing remote CLI commands or SSH X11 forwarding. It also must have 2 USB ports: 1 for the N900, 1 for the USB device (printer, camera, HDD, ...).
The second solution provides much less bandwith. Its an option I can use right now e.g. my DSL modem can get a USB HDD attached.
A dedicated project for this might be best. I think it could even integrate the hosting of the 3"5 SATA. OTOH, I don't take USB for data transfers too seriously... eSATA, FW, (i)SCSI, FC for me. Perhaps ZFS + iSCSI is a nice solution.
