Added a prepare method to the area detector FlyerMixin() class.

src/haven/instrument/area_detector.py

@@ -42,6 +42,7 @@
 from ophyd.areadetector.plugins import TIFFPlugin_V31, TIFFPlugin_V34
 from ophyd.flyers import FlyerInterface
 from ophyd.status import Status, StatusBase, SubscriptionStatus
+from ophyd_async.core import DetectorTrigger, TriggerInfo
 
 from .. import exceptions
 from .._iconfig import load_config
@@ -116,13 +117,22 @@ def save_fly_datum(self, *, value, timestamp, obj, **kwargs):
         datum = fly_event(timestamp=timestamp, value=value)
         self._fly_data.setdefault(obj, []).append(datum)
 
-    def kickoff(self) -> StatusBase:
+    def prepare(self, value: TriggerInfo) -> StatusBase:
+        assert (
+            value.trigger == DetectorTrigger.internal
+        ), f"Trigger mode {value.trigger} not supported."
+        status = self.cam.image_mode.set(ImageMode.CONTINUOUS)
+        status &= self.cam.num_images.set(value.number)
+        status &= self.cam.trigger_mode.set(self.flyscan_trigger_mode)
         # Set up subscriptions for capturing data
         self._fly_data = {}
         for walk in self.walk_fly_signals():
             sig = walk.item
             # Run subs the first time to make sure all signals are present
             sig.subscribe(self.save_fly_datum, run=True)
+        return status
+
+    def kickoff(self) -> StatusBase:
 
         # Set up the status for when the detector is ready to fly
         def check_acquiring(*, old_value, value, **kwargs):
@@ -134,9 +144,6 @@ def check_acquiring(*, old_value, value, **kwargs):
         status = SubscriptionStatus(self.cam.detector_state, check_acquiring)
         # Set the right parameters
         self._original_vals.setdefault(self.cam.image_mode, self.cam.image_mode.get())
-        status &= self.cam.image_mode.set(ImageMode.CONTINUOUS)
-        status &= self.cam.trigger_mode.set(self.flyscan_trigger_mode)
-        status &= self.cam.num_images.set(2**14)
         status &= self.cam.acquire.set(AcquireState.ACQUIRE)
         return status
 

src/haven/tests/test_area_detector.py

@@ -5,6 +5,7 @@
 from ophyd import ADComponent as ADCpt
 from ophyd.areadetector.cam import AreaDetectorCam
 from ophyd.sim import instantiate_fake_device
+from ophyd_async.core import DetectorTrigger, TriggerInfo
 
 from haven.instrument.area_detector import (
     DetectorBase,
@@ -25,16 +26,32 @@ def detector(sim_registry):
     return det
 
 
-def test_flyscan_kickoff(detector):
-    detector.flyer_num_points.set(10)
+@pytest.fixture()
+def trigger_info():
+    return TriggerInfo(
+        number=5, trigger=DetectorTrigger.internal, deadtime=0.2, livetime=1.3
+    )
+
+
+def test_flyscan_prepare(detector, trigger_info):
+    status = detector.prepare(trigger_info).wait(timeout=3)
+    # Check that the device was properly configured for fly-scanning
+    assert detector._fly_data == {}
+    # Check that signals were set up properly
+    assert detector.cam.image_mode.get() == 2
+    assert detector.cam.num_images.get() == 5
+    assert detector.cam.trigger_mode.get() == 0
+
+
+def test_flyscan_kickoff(detector, trigger_info):
+    detector.prepare(trigger_info).wait(timeout=1)
     status = detector.kickoff()
     detector.cam.detector_state.sim_put(DetectorState.ACQUIRE)
     status.wait(timeout=3)
     assert status.success
     assert status.done
     # Check that the device was properly configured for fly-scanning
     assert detector.cam.acquire.get() == 1
-    assert detector._fly_data == {}
     # Check that timestamps get recorded when new data are available
     detector.cam.array_counter.sim_put(1)
     event = detector._fly_data[detector.cam.array_counter]