Talk:Polling rate
I started a document some time back to remind myself of all the polling rates of the various USB interfaces (and PS/2). Still needs a bit of work on the math (and some validation to make sure it's correct before I think it's wiki quality). Perhaps some proper spec references for the USB polling rates as well. -HaaTa
Contents
PS/2
Interrupt based, usually. This is optional, and the OS can decide to poll the results from the PS/2 interface. The polling rate is likely around 125 Hz, but this is entirely dependent upon OS settings. Going from the PS/2 mouse protocol, this could be as bad as 10 Hz (possibly even worse).
Each 11 bit packet is around 900 us with a delay of at least 50 us between multiple packets (? not completely sure about this, depends on the keyboard implementation). This generally means about 1 ms per key, or 7 ms when pressing Ctrl + Alt + A + B + C + D + E.
Effective polling rate
Best case 1 key: 1000 Hz Best case 6 keys: 167 Hz Bad case 1 key: 10 Hz (due to OS polling)
References
- http://www.computer-engineering.org/ps2keyboard/
- http://www.computer-engineering.org/ps2protocol/
- http://wiki.osdev.org/%228042%22_PS/2_Controller
- http://wiki.osdev.org/PS/2
- http://wiki.osdev.org/PS/2_Keyboard
- http://wiki.osdev.org/Mouse_Input
USB 1.1/2.0 - Low Speed
Polling Rate: 125 Hz
Max Data Rate: 1.5 mbps
TODO - Data transmission analysis
USB 2.0 - Full Speed
Polling Rate: 1000 Hz
Max Data Rate: 12 mbps
USB 2.0 - Hi-Speed
Polling Rate: 8000 Hz
Max Data Rate: 480 mbps
TODO - Data transmission analysis
USB 3.0 - SuperSpeed (USB 3.1 Gen 1)
Polling Rate: 8000 Hz
Max Data Rate: 5 gbps
TODO - Data transmission analysis
USB 3.1 - SuperSpeed+ (USB 3.1 Gen 2)
Polling Rate: 8000 Hz
Max Data Rate: 10 gbps
TODO - Data transmission analysis
