The legacy joystick math left the output unchanged when the raw sample was
exactly 0 - a case a jittering pot never produces, so on real hardware the hold
was invisible. vRIO's pad deadzone produces it constantly: every release of the
bench gamepad shapes the residual to exactly 0.0 and holds it there, one sample
per 55 ms poll. The calibrator held the last in-motion output against that
stream indefinitely, so the virtual pad froze off-center at whatever the stick
commanded the instant before release.
Flown, that read as a Descent 3 pod drifting on yaw and pitch with the stick
centered, stopping only when the release was slow enough to land an
intermediate sample inside the +/-5 band. It survived a full day of suspects -
the game's deadzone, its axis map, its focus handling, com0com, the serial
protocol - because every layer below the calibrator was correct: the freeze was
visible in joy.cpl itself, and the game's own control trace showed heading
latched at -0.38 while the wire carried perfect zeros.
Same divergence from the legacy port, same reasoning, as the throttle detent
fix above it: zero means centered, not "no information". Both axes; regression
tests pin the fast-release case and center stability across repeated zero
polls.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
CydandClaude Opus 5
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