fix

laser_control/controller.py

@@ -31,8 +31,8 @@ from .constants import WAIT_AFTER_SEND_SEC
 logger = logging.getLogger(__name__)
 
 # Default PI regulator coefficients (match firmware defaults)
-DEFAULT_PI_P = 1
-DEFAULT_PI_I = 1
+DEFAULT_PI_P = 2560   # 10 * 256
+DEFAULT_PI_I = 128    # 0.5 * 256
 
 
 class LaserController:
@@ -150,7 +150,7 @@ class LaserController:
             pi_coeff2_i=self._pi2_i,
             message_id=self._message_id,
         )
-        self._send(cmd)
+        self._send_and_read_state(cmd)
         logger.debug("Manual mode set: T1=%.2f T2=%.2f I1=%.2f I2=%.2f",
                      validated['temp1'], validated['temp2'],
                      validated['current1'], validated['current2'])
@@ -228,7 +228,7 @@ class LaserController:
             pi_coeff2_p=self._pi2_p,
             pi_coeff2_i=self._pi2_i,
         )
-        self._send(cmd)
+        self._send_and_read_state(cmd)
         logger.info("Variation task started: type=%s min=%.3f max=%.3f step=%.3f",
                     validated['variation_type'].name,
                     validated['min_value'],
@@ -238,7 +238,7 @@ class LaserController:
     def stop_task(self) -> None:
         """Stop the current task by sending DEFAULT_ENABLE (reset)."""
         cmd = Protocol.encode_default_enable()
-        self._send(cmd)
+        self._send_and_read_state(cmd)
         logger.info("Task stopped (DEFAULT_ENABLE sent)")
 
     def get_measurements(self) -> Optional[Measurements]:
@@ -303,7 +303,7 @@ class LaserController:
     def reset(self) -> None:
         """Send a hardware reset command to the device."""
         cmd = Protocol.encode_default_enable()
-        self._send(cmd)
+        self._send_and_read_state(cmd)
         logger.info("Device reset command sent")
 
     # ---- Internal helpers -------------------------------------------------
@@ -315,6 +315,23 @@ class LaserController:
         self._protocol.send_raw(cmd)
         time.sleep(WAIT_AFTER_SEND_SEC)
 
+    def _send_and_read_state(self, cmd: bytes) -> int:
+        """Send command and read the 2-byte STATE response the device always returns.
+
+        Commands DECODE_ENABLE, TASK_ENABLE and DEFAULT_ENABLE each trigger a
+        STATE reply from the firmware.  If we don't consume those bytes here,
+        they accumulate in the serial buffer and corrupt the next DATA read.
+
+        Returns the decoded state code (0x0000 = OK).
+        """
+        self._send(cmd)
+        raw = self._protocol.receive_raw(2)
+        if raw and len(raw) == 2:
+            state = Protocol.decode_state(raw)
+            logger.debug("STATE response after command: 0x%04x", state)
+            return state
+        return 0
+
     # ---- Context manager support -----------------------------------------
 
     def __enter__(self):

pyproject.toml

@@ -1,6 +1,6 @@
 [build-system]
 requires = ["setuptools"]
-build-backend = "setuptools.backends.legacy:build"
+build-backend = "setuptools.build_meta"
 
 [project]
 name = "laser_control"