diff --git a/pico-cp/README.md b/pico-cp/README.md
index 67098eb..36dd9d0 100644
--- a/pico-cp/README.md
+++ b/pico-cp/README.md
@@ -122,9 +122,10 @@ The Kit can drive a **physical metronome pendulum**: a 4-input unipolar stepper
     power‑cycle.
 - **Jog / test mode** (hold **A + B** at boot): the joystick sets **direction only** — **L = CCW, R = CW** — and
   the motor **accelerates to `STEPPER_MAX_RATE`** (reversing decelerates through zero first), with an on‑screen
-  needle + RGB LED and a **live step counter + rate readout**. *Tuning:* raise `STEPPER_MAX_RATE` until the
-  motor starts skipping, then back off; if it stalls *starting*, lower `STEPPER_ACCEL` / `STEPPER_JOG_START`.
-  Power‑cycle (no buttons) to exit.
+  needle + RGB LED. The **step count + peak‑rate readout updates when you release** (drawing mid‑spin would
+  stall the step loop and make it jumpy, so the spin itself stays glitch‑free). *Tuning:* hold to spin, release
+  to read the peak; raise `STEPPER_MAX_RATE` until the motor skips, then back off; if it stalls *starting*,
+  lower `STEPPER_ACCEL` / `STEPPER_JOG_START`. Power‑cycle (no buttons) to exit.
 
 ## programs.json
 
diff --git a/pico-cp/app.py b/pico-cp/app.py
index 66a72ee..f6df469 100644
--- a/pico-cp/app.py
+++ b/pico-cp/app.py
@@ -1179,8 +1179,9 @@ class App:
         # Joystick = DIRECTION only (no fine speed). Spin at STEPPER_MAX_RATE, reached via an
         # acceleration ramp (STEPPER_ACCEL) so the motor doesn't stall trying to start at top speed;
         # reversing decelerates through zero, then accelerates the other way.
-        spin = 0; cur = 0.0; total = 0; win = 0; peak = 0
+        spin = 0; cur = 0.0; total = 0; win = 0; peak = 0; lastrate = 0
         now = time.monotonic(); last = now; tsample = now; tjoy = now
+        gc.collect()                                        # clean heap before spinning (avoid a GC pause mid-spin)
         while True:                                         # no per-iteration sleep: tight step timing in this mode
             now = time.monotonic()
             if now - tjoy >= 0.004:                         # control update (joystick + accel), off the step hot-path
@@ -1194,15 +1195,16 @@ class App:
                 elif cur > target: cur = max(0.0, cur - STEPPER_ACCEL * cdt)     # decelerate
                 if cur <= 0.0 and spin != 0 and want != spin:   # finished slowing -> stop, or flip direction
                     if self.pend is not None and self.pend.ok: self.pend.release()
-                    if want == 0: spin = 0; set_needle(0)
-                    else: spin = want; cur = float(STEPPER_JOG_START); set_needle(spin)
+                    if want == 0:                       # stopped -> now safe to draw the readout + tidy the heap
+                        spin = 0; show_stats(total, lastrate, peak); set_needle(0); gc.collect()
+                    else:
+                        spin = want; cur = float(STEPPER_JOG_START); set_needle(spin)
             if spin != 0 and cur > 0.0 and self.pend is not None and self.pend.ok and now - last >= 1.0 / cur:
                 self.pend.spin(spin > 0); last = now; total += 1; win += 1
-            if now - tsample >= 1.0:                         # step-rate readout, once/s (one tiny refresh)
-                rate = int(win / (now - tsample))
-                if rate > peak: peak = rate
-                show_stats(total, rate, peak); win = 0; tsample = now
-                self.display.refresh()
+            if now - tsample >= 1.0:                         # measure rate SILENTLY (drawing here is what hitched it)
+                lastrate = int(win / (now - tsample))
+                if lastrate > peak: peak = lastrate
+                win = 0; tsample = now
 
     # ---------- audio + light ----------
     def click(self, level):