fixes

avr_code/interrupts.c

@@ -56,9 +56,11 @@ void wdt_isr_enable(void)
     MCUSR &= ~(1 << WDRF);
     WDTCSR = (1 << WDCE) | (1 << WDE);
 
-    // WDP[3:0] = 0b011 -> 0.125 s. Interrupt mode only (WDE clear), so an
-    // expiry wakes us to clear the debounce instead of resetting the part.
-    WDTCSR = (1 << WDIE) | (1 << WDP1) | (1 << WDP0);
+    // WDP[3:0] = 0b010 -> 64 ms debounce, capping the count at ~15 rev/s;
+    // a reed contact settles in a few ms, so this is generous. Interrupt mode
+    // only (WDE clear): an expiry wakes us to clear the debounce instead of
+    // resetting the part.
+    WDTCSR = (1 << WDIE) | (1 << WDP1);
 
     SREG = sreg; // Restore, never blanket-sei(): these run inside an ISR
 }