1000hz polling rate on USB 2.0?

[Borgus Bohr]

From a mouse perspective. Is usb 2.0 good enough for polling rates of 1000hz? Would usb 3.0 make a difference?

 

[thekingofmonks]

usb 2.0 caps at 60mbytes/sec, which is overkill for 1000Hz but also the minimum version for it to work properly.

[TheChromaBristlenose]

20 hours ago, thekingofmonks said:

usb 2.0 caps at 60mbytes/sec, which is overkill for 1000Hz but also the minimum version for it to work properly.

Data transfer rates are irrelevant for the OP's question, since polling packets are tiny. What matters is the minimum transaction interval - USB 1.1 was the first to support the "Full-Speed" standard, which allowed 1ms polling intervals (1000hz). USB 2.0 supports both "Full-Speed" and "High-Speed", the latter of which allows 125μs intervals (8000hz). So a 1000hz, "Full-Speed" mouse is nowhere near maxing out the capabilities of USB 2.0.

 

USB 3 hasn't been used for any mice that I'm aware of, since it offers no real benefit over USB 2. While the data transfer rate is significantly higher, mice don't take advantage of that, and the transfer intervals remain capped at 125μs (8000hz) which is something USB 2 is already capable of. 

[thekingofmonks]

4 hours ago, TheChromaBristlenose said:

So a 1000hz, "Full-Speed" mouse is nowhere near maxing out the capabilities of USB 2.0.

This totally makes transfer rates relevant:

Despite usb1.1 allowing speeds up to 1.5mbytes, it's still a narrow bus that makes mouse movement extremely choppy when other devices are connected and running on the same hub. The same occurs with usb 2.0 except it's far less significant with better signal integrity and a much wider bus.

[Just that Mario]

On 1/14/2022 at 6:10 AM, thekingofmonks said:

This totally makes transfer rates relevant:

Despite usb1.1 allowing speeds up to 1.5mbytes, it's still a narrow bus that makes mouse movement extremely choppy when other devices are connected and running on the same hub. The same occurs with usb 2.0 except it's far less significant with better signal integrity and a much wider bus.

Isn't that more of an PC/Motherboard issue than the peripheral itself?

[thekingofmonks]

16 hours ago, Just that Mario said:

Isn't that more of an PC/Motherboard issue than the peripheral itself?

Yes, usb controller is outdated, unstable, etc.

[Borgus Bohr]

On 1/13/2022 at 6:02 PM, TheChromaBristlenose said:

Data transfer rates are irrelevant for the OP's question, since polling packets are tiny. What matters is the minimum transaction interval - USB 1.1 was the first to support the "Full-Speed" standard, which allowed 1ms polling intervals (1000hz). USB 2.0 supports both "Full-Speed" and "High-Speed", the latter of which allows 125μs intervals (8000hz). So a 1000hz, "Full-Speed" mouse is nowhere near maxing out the capabilities of USB 2.0.

 

USB 3 hasn't been used for any mice that I'm aware of, since it offers no real benefit over USB 2. While the data transfer rate is significantly higher, mice don't take advantage of that, and the transfer intervals remain capped at 125μs (8000hz) which is something USB 2 is already capable of. 

Thanks for the detailed answer. Good to know how much time is a 1000hz polling rate (1ms).  I didn't thought of looking at it this way.

[IPD]

The migration will happen eventually.  Once computers only have USB4, peripherals will end up switching to c-type or risk irking their customers by requiring adapters.  Then again, USB>PS2 adapters still exist...for some unholy reason...just like the PS2 interface.