Timeline for Emulate USB device with USB host
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Mar 5, 2013 at 17:08 | comment | added | Ben Voigt | USB OTG is not "just specialized software". Pull-up and pull-down resistors are required in different places, in addition to the different semantic behavior required of device vs host. The connection to VBUS is totally different as well between host and device. -1 | |
| Feb 4, 2013 at 3:53 | comment | added | Chris Stratton | No, the only unsupported claim here is that this would be possible on typical computers. You are ignoring that this has been demonstrated on embedded devices with low-latency GPIO optimized for real-world interaction, not on more complicated systems with I/O's neither intended nor suitable for bit-banging type usage even at clock rates a small fraction of the lowest USB speed. Embedded engineers develop an extreme experience-driven awareness of such distinctions, as it's essential to picking appropriate platforms for systems, and even their mockups/test harnesses. | |
| Feb 3, 2013 at 23:01 | comment | added | Passerby | @ChrisStratton and it's disrespectful to answer with "we just know" when someone asks you to back up your claims | |
| Feb 3, 2013 at 22:37 | comment | added | Chris Stratton | @Passerby - the lack of low-latency GPIO on modern computers is well known to everyone who works in the embedded and control fields, as its a major example of how technology has moved backwards in versatility, with things that used to be possible on older systems ceasing to be possible on newer ones as the increasingly faster CPU becomes increasingly more isolated from the real world. | |
| Feb 3, 2013 at 22:35 | comment | added | Passerby | How about a citation for that @ChrisStratton | |
| Feb 3, 2013 at 22:29 | comment | added | Chris Stratton | Incorrect. You cannot even remotely bitbang USB on most modern computers, as you don't have sufficiently realtime access to any GPIOs. That's become the exclusive domain of embedded microcontrollers with real I/O hanging directly off the processor, instead of at arms length downstream of some bridge device as is done in modern general purpose computers. | |
| Feb 3, 2013 at 4:53 | comment | added | Passerby | Well, considering this is a thought exercise instead of practical design, that's not a problem. USB OTG doesn't require any special hardware any more than USB itself does (you can bitbang USB). And if you can use the USB pins as GPIO with direct hardware control, you could use software to turn it into a usb slave device. It's not practical, but possible. | |
| Feb 3, 2013 at 2:48 | comment | added | Chetan Bhargava | USB OTG is not present on computers unless specifically added by using an extra piece of hardware. | |
| Feb 2, 2013 at 23:51 | history | answered | Passerby | CC BY-SA 3.0 |