Switch the PPK2_MP class to use threading to fix Issue 18. The PPK2_MP can now be used on windows and fixes a possible issue with queue sync on linux platforms

Author: Matthew Beaudoin

src/ppk2_api/ppk2_api.py

@@ -3,14 +3,14 @@
 The PPK2 uses Serial communication.
 The official nRF Connect Power Profiler was used as a reference: https://github.com/NordicSemiconductor/pc-nrfconnect-ppk
 """
-
+import threading
 import time
 import serial
 import struct
 import logging
 import os
 import queue
-import multiprocessing
+
 
 class PPK2_Command():
     """Serial command opcodes"""
@@ -243,7 +243,7 @@ def stop_measuring(self):
         self._write_serial((PPK2_Command.AVERAGE_STOP, ))
 
     def set_source_voltage(self, mV):
-        """Inits device - based on observation only REGULATOR_SET is the command. 
+        """Inits device - based on observation only REGULATOR_SET is the command.
         The other two values correspond to the voltage level.
 
         800mV is the lowest setting - [3,32] - the values then increase linearly
@@ -290,7 +290,7 @@ def get_adc_result(self, current_range, adc_value):
             self.rolling_avg = adc
         else:
             self.rolling_avg = self.spike_filter_alpha * adc + (1 - self.spike_filter_alpha) * self.rolling_avg
-        
+
         if self.rolling_avg4 is None:
             self.rolling_avg4 = adc
         else:
@@ -313,7 +313,7 @@ def get_adc_result(self, current_range, adc_value):
                 adc = self.rolling_avg4
             else:
                 adc = self.rolling_avg
-            
+
             self.after_spike -= 1
 
         self.prev_range = current_range
@@ -358,9 +358,9 @@ def get_samples(self, buf):
         return samples  # return list of samples, handle those lists in PPK2 API wrapper
 
 
-class PPK_Fetch(multiprocessing.Process):
+class PPK_Fetch(threading.Thread):
     '''
-    Background process for polling the data in multiprocessing variant
+    Background process for polling the data in multi-threading variant
     '''
     def __init__(self, ppk2, quit_evt, buffer_len_s=10, buffer_chunk_s=0.5):
         super().__init__()
@@ -380,7 +380,7 @@ def __init__(self, ppk2, quit_evt, buffer_len_s=10, buffer_chunk_s=0.5):
         if self._buffer_chunk % 4 != 0:
             self._buffer_chunk = (self._buffer_chunk // 4) * 4
 
-        self._buffer_q = multiprocessing.Queue()
+        self._buffer_q = queue.Queue()
 
     def run(self):
         s = 0
@@ -442,7 +442,7 @@ def __init__(self, port, buffer_seconds=10):
         '''
         super().__init__(port)
         self._fetcher = None
-        self._quit_evt = multiprocessing.Event()
+        self._quit_evt = threading.Event()
         self._buffer_seconds = buffer_seconds
 
     def __del__(self):
@@ -466,7 +466,7 @@ def start_measuring(self):
         self._quit_evt.clear()
         if self._fetcher is not None:
             return
-        
+
         self._fetcher = PPK_Fetch(self, self._quit_evt, self._buffer_seconds)
         self._fetcher.start()