Updated debounce and flash script

rp2040/src/board.rs

@@ -86,6 +86,7 @@ impl Board {
             hardware::MATRIX_DEBOUNCE_SCANS_PRESS,
             hardware::MATRIX_DEBOUNCE_SCANS_RELEASE,
             hardware::MIN_PRESS_SPACING_SCANS,
+            hardware::RELEASE_GRACE_PERIOD_SCANS,
         );
         button_matrix.init_pins();
 

rp2040/src/button_matrix.rs

@@ -63,8 +63,10 @@ pub struct ButtonMatrix<P, const ROWS: usize, const COLS: usize, const KEYS: usi
     release_threshold: u8,
     debounce_counter: [u8; KEYS],
     last_press_scan: [u32; KEYS],
+    last_release_scan: [u32; KEYS],
     scan_counter: u32,
     min_press_gap_scans: u32,
+    release_grace_period_scans: u32,
 }
 
 impl<P, const ROWS: usize, const COLS: usize, const KEYS: usize> ButtonMatrix<P, ROWS, COLS, KEYS>
@@ -76,6 +78,7 @@ where
         press_threshold: u8,
         release_threshold: u8,
         min_press_gap_scans: u32,
+        release_grace_period_scans: u32,
     ) -> Self {
         debug_assert_eq!(KEYS, ROWS * COLS);
         Self {
@@ -85,8 +88,10 @@ where
             release_threshold,
             debounce_counter: [0; KEYS],
             last_press_scan: [0; KEYS],
+            last_release_scan: [0; KEYS],
             scan_counter: 0,
             min_press_gap_scans,
+            release_grace_period_scans,
         }
     }
 
@@ -133,7 +138,11 @@ where
             if self.debounce_counter[button_index] >= threshold {
                 self.pressed[button_index] = match current_state {
                     true => self.should_register_press(button_index),
-                    false => false,
+                    false => {
+                        // Track release events for grace period
+                        self.last_release_scan[button_index] = self.scan_counter;
+                        false
+                    }
                 };
                 self.debounce_counter[button_index] = 0;
             }
@@ -145,9 +154,13 @@ where
     }
 
     fn should_register_press(&mut self, button_index: usize) -> bool {
-        let elapsed = self.scan_counter.wrapping_sub(self.last_press_scan[button_index]);
-        let can_register = self.last_press_scan[button_index] == 0
-            || elapsed >= self.min_press_gap_scans;
+        let press_elapsed = self.scan_counter.wrapping_sub(self.last_press_scan[button_index]);
+        let release_elapsed = self.scan_counter.wrapping_sub(self.last_release_scan[button_index]);
+        
+        let can_register = (self.last_press_scan[button_index] == 0
+            || press_elapsed >= self.min_press_gap_scans)
+            && (self.last_release_scan[button_index] == 0
+                || release_elapsed >= self.release_grace_period_scans);
 
         if can_register {
             self.last_press_scan[button_index] = self.scan_counter;
@@ -211,7 +224,7 @@ mod tests {
         let row_state = Rc::new(Cell::new(false));
         let column_state = Rc::new(Cell::new(false));
         let pins = MockMatrixPins::new(row_state.clone(), column_state.clone());
-        let matrix = ButtonMatrix::new(pins, 5, 5, 200);
+        let matrix = ButtonMatrix::new(pins, 5, 5, 200, 100);
         (matrix, row_state, column_state)
     }
 

rp2040/src/hardware.rs

@@ -7,13 +7,17 @@ use rp2040_hal::gpio::Pins;
 pub const XTAL_FREQ_HZ: u32 = 12_000_000;
 
 /// Debounce scans required before a key state toggles.
-/// Increased from 2/3 to 5/5 to prevent double characters from key bounce.
-/// At 250μs scan rate: 5 scans = 1.25ms debounce time.
-pub const MATRIX_DEBOUNCE_SCANS_PRESS: u8 = 5;
-pub const MATRIX_DEBOUNCE_SCANS_RELEASE: u8 = 5;
+/// Increased from 5/5 to 8/8 to prevent double characters from key bounce.
+/// At 250μs scan rate: 8 scans = 2ms debounce time.
+pub const MATRIX_DEBOUNCE_SCANS_PRESS: u8 = 8;
+pub const MATRIX_DEBOUNCE_SCANS_RELEASE: u8 = 8;
 
-/// Minimum scans between two press events for the same key (50ms at 250μs scan cadence).
-pub const MIN_PRESS_SPACING_SCANS: u32 = 200;
+/// Minimum scans between two press events for the same key (75ms at 250μs scan cadence).
+pub const MIN_PRESS_SPACING_SCANS: u32 = 300;
+
+/// Grace period after key release before allowing new press (37.5ms at 250μs scan cadence).
+/// This prevents phantom presses from release bounce.
+pub const RELEASE_GRACE_PERIOD_SCANS: u32 = 150;
 
 /// Initial scan iterations before trusting key state.
 pub const INITIAL_SCAN_PASSES: usize = 50;

rp2040/src/status.rs

@@ -354,7 +354,7 @@ mod tests {
     #[test]
     fn idle_mode_backdates_start_time() {
         // Idle mode should start mid-breath so the LED resumes smoothly.
-        let now = 10_000;
+        let now: u32 = 10_000;
         let expected = now.saturating_sub(BREATH_PERIOD_MS / 2);
         assert_eq!(mode_start_time(StatusMode::Idle, now), expected);
         assert_eq!(mode_start_time(StatusMode::Active, now), now);

tools/copy_uf2.py

@@ -41,9 +41,13 @@ def candidate_paths(explicit: str, user: str) -> list[Path]:
         if not root.exists() or not root.is_dir():
             continue
         # Many systems mount the UF2 volume directly as a child of the root directory.
+        try:
             for child in root.iterdir():
                 if child.is_dir():
                     paths.append(child)
+        except PermissionError:
+            # Skip directories we can't read
+            continue
     return paths
 
 
@@ -53,13 +57,11 @@ def choose_mount(explicit: str, user: str) -> Path | None:
         # For an explicit mount we only care whether it exists.
         path = Path(explicit)
         return path if path.exists() and path.is_dir() else None
-    # Prefer candidates containing INFO_UF2.TXT, fall back to first existing directory.
+    # Only accept candidates containing INFO_UF2.TXT (real RP2040 bootloader mounts)
     info_candidates = [path for path in candidates if (path / INFO_FILE).exists()]
     if info_candidates:
         return info_candidates[0]
-    for path in candidates:
-        if path.exists() and path.is_dir():
-            return path
+    # Don't fall back to random directories - only accept real RP2040 mounts
     return None
 
 
@@ -104,9 +106,13 @@ def main() -> int:
         )
     else:
         print(
-            "Unable to detect RP2040 UF2 mount. Pass one via mount=/path",
+            "Unable to detect RP2040 UF2 mount. Make sure device is in bootloader mode:",
             file=sys.stderr,
         )
+        print("1. Press reset/boot button on rp2040 Zero board", file=sys.stderr)
+        print("2. Press upper left corner key when connecting USB", file=sys.stderr)
+        print("3. Press Fn+Fn+Shift+Shift+Ctrl chord", file=sys.stderr)
+        print("Then try again or pass explicit mount via mount=/run/media/$USER/RPI-RP2", file=sys.stderr)
     return 1