Re: Q: How does USB hubs work? Re: Multiple USB Devices
On Sat, Feb 03, 2007 at 09:15:54AM -0700, Joe Pfeiffer wrote: Harald Welte writes: My understanding is that it will be USB On-The-Go, No. OTG is a complex specification, and it comprises way more than just a AB socket, but also electrical and software components which we cannot provide using the S3C2410. Thanks for the correction. This is interesting do I understand you to mean that the NEO can behave as either a host or as a device depending on how it's plugged in, without support OTG? Yes. OTG is one specific, quite complicated (on multiple layers) approach to automatically do the right thing, if you have compliant devices. We're basically able to electrically switch the usb socket from host to device and vice-versa, 1) manually (by software) 2) automatically in OTG-similar way based on 5th pin of mini-B jack. but we cannot do all the higher layers (such as negotiating with another device who will be host and who will be device, etc.) -- - Harald Welte [EMAIL PROTECTED] http://openmoko.org/ Software for the world's first truly open Free Software mobile phone ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Q: How does USB hubs work? Re: Multiple USB Devices
On Wed, Jan 31, 2007 at 08:20:04AM -0700, Joe Pfeiffer wrote: Robert Michel writes: Brilliant! Thanks for that :-) So now the question, how does an USB hub work? Can we plug in the host on any port? Short form: USB is strictly a hierarchical, tree-structured network. There is one host, which may connect to the upstream port on a hub; you can then plug in more hubs and devices downstream of the hub. They were very careful when writing to the standard to specify cables that can't plug in the wrong way: you can only plug a host into the (single) upstream port on the hub. Long form: http://viper.cs.nmsu.edu:8000/classes/473/notes/usb.php?currentsem=s06 Really long form (this is the USB 2.0 specification) http://www.usb.org/developers/docs/usb_20_05122006.zip The Neo1973 will have mini-USB-B normal hubs powered USB-A for the adapter and one unpowerd USB-B for the host. My understanding is that it will be USB On-The-Go, No. OTG is a complex specification, and it comprises way more than just a AB socket, but also electrical and software components which we cannot provide using the S3C2410. All you need is a special Mini-B to regular-B cable, which you then can plug in the upstream port of any regular self-powered USB hub.You can then use any (low-speed,full-speed) usb device on that hub. But that normal hub will not charge the phone, though. FIC product development is looking in providing something that conveniently solves this problem. I cannot say more than that at this point :) -- - Harald Welte [EMAIL PROTECTED] http://openmoko.org/ Software for the world's first truly open Free Software mobile phone ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Q: How does USB hubs work? Re: Multiple USB Devices
Salve! On Wed, 31 Jan 2007, Michael Fletcher wrote: I was wondering, I have been searched the mailing list, but can't seem to find an answer. Will it be possible to connect a powered USB HUB into the 1973. So that for example the phone can charge, have a USB WiFi dongle attached and a USB mouse/keyboard all connected at the same time? yes. Brilliant! Thanks for that :-) So now the question, how does an USB hub work? Can we plug in the host on any port? The Neo1973 will have mini-USB-B normal hubs powered USB-A for the adapter and one unpowerd USB-B for the host. So to connect the Neo with a PC we have a mini-USB-B to USB-A cable. 1.) Can we plug the Neo with USB-A it into the (battery powered) hub and charge it whith it? (I think yes) 2.) Can we plug the Neo with USB-A it into the (battery powered) hub and use an USB device plugged into the hub? So reducing the USB connector and adapter mess... we could modifiy a (battery powered) hub in a way that on USB-A port will be an unpowered one (or just switchable power). Then could we deccide if we want to charge the Neo with the hub or not. (And we don't need a mini-USB-B to USB-B cable/adapeter) So how behave USB hubs? Just stupied forwarding to every port, no special host port (internaly)? Greetings rob PS: And what would happen when two hosts are connected to one hub? ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
