74 lines
1.6 KiB
Markdown
74 lines
1.6 KiB
Markdown
I did some performance testing.
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The Pro Micro runs an Atmel 32u4 at 8MHz.
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If the code does nothing else,
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I was able to poll all pins around 13 times every 1ms,
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or 13kHz.
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Sample Rate
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-----------
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The number of samples taken since the last HID report
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is sent as the second Y axis.
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If you use the
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[included gamepad tester](gamepad.html),
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it will show the approximate number of samples as an integer,
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for Y axis 2.
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This is approximate,
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because the browser encodes the value as a real number between -1 and 1.
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We convert it back, but may lose a little precision.
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It's close enough for me,
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hopefully it's close enough for you.
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Debouncing
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----------
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Using `millis()` time to debounce the switch
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roughly halved my sample frequency.
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So instead, I do some preprocessor arithmetic
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to calculate how many samples to take after an edge,
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in order to debounce switches.
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The drum controller was a partcular pain:
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in addition to the switch bouncing,
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the stick was bouncing on the rubber pad.
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I settled on a 40ms silence window as feeling pretty good.
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You can adjust this if you want to.
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Gamepad Buttons
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---------------
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The `buttons` struct member is a bitmap,
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each bit mapping to one of the 12 buttons reported through HID.
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Here's what each bit means:
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* 0: Blue
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* 1: Green
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* 2: Red
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* 3: Yellow
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* 4: Orange
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* 5: Tilt Switch / 2x kick
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* 6: Solo modifier (second row of buttons on guitar)
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* 7: ?
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* 8: Minus
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* 9: Plus
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* 10: Drum pad modifier?
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* 11: Cymbal modifier?
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* 12: ?
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hatAndConstant
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--------------
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I don't get this, but here's what the values mean:
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* 2: right
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* 6: left
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* 0: up
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* 4: down
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* 8: nothing
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