Electronics > Beginners
Question by interface USB-3
alex 54:
Hello,i want to ask a question by interface USB-3
I'm a beginner programmer, I'm sorry if the question sounds silly, because the information on the Internet is not enough for this issue.
I recently made a USB 2 gaming device (the picture is attached), and it turned out very successful mainly because of the high 0.8 ms, the polling frequency of this device.
Then I decided to explore the possibilities of the USB 3 interface.
Purpose: to achieve the fastest transfer of information (which is only 8 bytes in size) to the program (game).
Technically, i can do it like,but will the USB 3 device have some advantage over USB 2 in the speed of information transfer from the microcontroller to the program (game), taking into account the latency of Windows?
Sincerely, Alex 54.
timgiles:
The latency caused by windows itself wont change, at least once the hardware USB chips have received the data, passed through to the motherboard USB device driver and then in to the windows OS/application stack. The length of time to transmit/receive the data will of course be shorter but for a gaming device (is this emulating a HID device like a keyboard, joystick, mouse?) I dont see that you will be transmitting much data or very many packets per second - so I am not sure the reduction in total latency will prove to be significant. Seems like a sledgehammer to crack a nut. Also USB 3 implemented on your device requires differential pairs routing with much more stringent trace length matching requirements...
andersm:
I can't read Russian, but doesn't the picture show your device operating only at USB full speed? Going to high speed should allow for a decent latency reduction and be easier to implement.
wraper:
Not only USB3 won't provide any advantage for input devices, I'm sure you aren't even utilizing potential of USB2.0. I'm pretty sure you are using USB full speed mode (12mbps). Anyway most programs cannot really utilize 1000Hz HID report rate anyway.
--- Quote ---I recently made a USB 2 gaming device (the picture is attached), and it turned out very successful mainly because of the high 0.8 ms, the polling frequency of this device.
Then I decided to explore the possibilities of the USB 3 interface.
--- End quote ---
It's 1000 reports per second really (1000 Hz polling rate). You cannot do more with HID.
alex 54:
Dear gentlemen, thank you for participating in the discussion of the topic.
I'll tell you why I asked a question about USB-3.
When I made the USB-2 gaming device shown in the picture above,
I managed to implement in it all the maximum parameters for this class.
The first 30 minute combat sortie (I play a serious simulator) showed an undoubted advantage over other players. The picture below, = S = Alex it's me.
Testing the gaming device showed that this result was obtained
due to the high polling frequency of the device (the higher the polling frequency, the smoother control, and therefore less speed loss, the main advantage in combat).
The polling frequency of my device is maximal for USB-2, based on the test program it is 1250 Hz.
Maybe it happened because I used a high-quality microcontroller XMega, with hardware support for USB, I do not know.
But not every gaming device has a similar parameter.
That's why I was interested in USB-3, because if I could double
parameter 1250 Hz, it would turn out not a device but a bomb.
I felt that the frequency of 1000 Hz for a HID was selected for a reason,
but I wanted to investigate the question on USB-3 and get an answer why it is impossible to change the parameter of interest to me.
And one more interesting fact about the made device USB-2:
Due to the fact that I used as sensors incremental
encoders, it was possible to realize auto-calibration and also the guidance system which has an accuracy of 0.0009 degrees, all this is not only my merit, my leader of this project is a very talented person.
Once again many thanks to all, with respect, Alex 54.
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