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fix(filter-wheel): reset W/W2 range to full after home (rotary axis) — fixes intermittent post-home CMD_EXECUTION_ERROR #560

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fix(filter-wheel): reset W/W2 range to full after home (rotary axis) — fixes intermittent post-home CMD_EXECUTION_ERROR #560

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5 changes: 4 additions & 1 deletion firmware/controller/src/constants.h
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Original file line number Diff line number Diff line change
Expand Up @@ -12,8 +12,11 @@
// Version 1.2 = CMD_EXECUTION_ERROR reported on failed moves + MOVETO_W2 command
// Version 1.3 = strobe ISR latches illumination source at start (race fix when
// channel switched during live HW-triggered acquisition)
// Version 1.4 = filter-wheel (W/W2) home resets xmin/xmax to full range (rotary
// axis has no travel end-stop); fixes intermittent post-home
// MOVETO_W CMD_EXECUTION_ERROR (home left xmin = L - C > offset)
Comment on lines +15 to +17

@Alpaca233 Alpaca233 Jun 18, 2026

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[Claude Code] Updated the PR title + description to match the code. The back-off state machine (is_backing_off_, back_off_homing_) was intentionally removed: hardware testing showed it only fixed the pressed-at-entry subcase — a released-at-entry home still failed (firmware v1.4 back-off build) — so it was dropped in favor of this version-independent root-cause fix (reset the rotary wheel's xmin/xmax to full range after home). The implemented diff is exactly that + the version bump; no missing code.

#define FIRMWARE_VERSION_MAJOR 1
#define FIRMWARE_VERSION_MINOR 3
#define FIRMWARE_VERSION_MINOR 4

#include "def/def_v1.h"

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14 changes: 14 additions & 0 deletions firmware/controller/src/operations.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -375,6 +375,17 @@ void finalize_homing_w()
tmc4361A_write_encoder(&tmc4361[w], 0);
if (stage_PID_enabled[w])
tmc4361A_set_PID(&tmc4361[w], PID_BPG0);
// The filter wheel is ROTARY (no travel end-stop) -- the linear-stage
// [xmin,xmax] range gate in tmc4361A_moveTo does not apply to it. Homing
// leaves xmin = L - C (L = press-latch position, C = release-detect
// position); a stale/mis-ordered latch makes xmin exceed the small absolute
// post-home offset target, so MOVETO_W is wrongly rejected with
// CMD_EXECUTION_ERROR. Reset to full range so valid rotary moves are never
// range-rejected. Safe: W xmin/xmax are written only in check_homing_w and
// consumed only by the moveTo range check (check_limits acts on X/Y/Z only,
// stopping them on a limit-switch event, and never touches W/W2).
tmc4361[w].xmin = INT32_MIN;
tmc4361[w].xmax = INT32_MAX;
}
W_pos = 0;
is_homing_W = false;
Expand All @@ -393,6 +404,9 @@ void finalize_homing_w2()
tmc4361A_write_encoder(&tmc4361[w2], 0);
if (stage_PID_enabled[w2])
tmc4361A_set_PID(&tmc4361[w2], PID_BPG0);
// Rotary wheel: no travel end-stop -> full range (see finalize_homing_w).
tmc4361[w2].xmin = INT32_MIN;
tmc4361[w2].xmax = INT32_MAX;
}
W2_pos = 0;
is_homing_W2 = false;
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