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Stella input response vs. real - measured

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#26 dualcam OFFLINE  


    Chopper Commander

  • Topic Starter
  • 159 posts

Posted Fri Jan 11, 2013 11:26 AM

A new test to focus on the USB and avoid the video delays. The on/off state of the NUM-, CAP-, & SCROLL-LOCK LEDs on a keyboard are controlled by the OS. I reprogrammed an adaptor to act as a keyboard. Pressing a switch transmits a NUM-LOCK key press. The OS processes that and sends back the NUM-LOCK state (on or off). The adaptor then receives that and sets it's LED acts as the keyboard NUM-LOCK LED. It might have been nice to have a test with a joystick, to keep it apples to apples, but I would contend that to the USB it is just packets of data to move from point A to B.

The measured round time, switch press to LED turn on/off, was usually 2ms and with an occasional 3ms. One thing about USB is it uses 1ms time frames and transmissions are at 1ms intervals, and I take this was the cause of the measured time to be in whole 1ms intervals.

That test was an unloaded system. Tried again with 99-100% CPU usage, and still got mostly 2ms with the occasional 3ms. So not affected by a busy CPU.


#27 Schizophretard OFFLINE  


    River Patroller

  • 3,349 posts

Posted Wed Jan 23, 2013 6:46 AM

The test should definitely include a CRT to be accurate. If it is real console vs emulation then an LCD shouldn't be used. It should be hooked up to the kind of display it was designed for. Otherwise, it is more like LCD vs emulation.

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