diff --git a/mipi_test.py b/mipi_test.py
index 0064777..c472eaf 100644
--- a/mipi_test.py
+++ b/mipi_test.py
@@ -176,23 +176,22 @@ def _set_timebase(scale, points):
 
 def _arm_and_wait(timeout=20):
     """
-    Fire a single acquisition and block until the scope stops (trigger + capture done).
-    Returns True on success, False on timeout.
+    Fire a single acquisition using :DIGitize (blocking on Infiniium) and
+    confirm completion with *OPC?.  Temporarily extends scope.timeout to
+    cover the full wait period.
+    Returns True on success, False on error/timeout.
     """
-    scope.write(":SINGle")
-    deadline = time.time() + timeout
-    while time.time() < deadline:
-        try:
-            # OPERegister bit 3 (mask 0x08) = instrument is running/armed.
-            # When it clears the acquisition is complete.
-            cond = int(scope.ask(":OPERegister:CONDition?").strip())
-            if not (cond & 0x08):
-                return True
-        except Exception:
-            pass
-        time.sleep(0.25)
-    print("  WARNING: ACQUISITION TIMEOUT — SCOPE MAY NOT HAVE TRIGGERED.")
-    return False
+    prev_timeout = scope.timeout
+    try:
+        scope.timeout = timeout + 5   # headroom over the DIGitize wait
+        scope.write(":DIGitize")
+        resp = scope.ask("*OPC?").strip()
+        return resp == "1"
+    except Exception as e:
+        print(f"  ACQUIRE ERROR: {e}")
+        return False
+    finally:
+        scope.timeout = prev_timeout
 
 
 def _save_pass(tag, iteration, ts):