feat(example): Generic synchronization example

Author: lilesj

nixnet_examples/generic_synchronization.py

@@ -0,0 +1,105 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import time
+
+import six
+
+import nixnet
+from nixnet import constants
+from nixnet import types
+
+
+def main():
+    interface1 = 'CAN1'
+    interface2 = 'CAN2'
+
+    #Create the objects for the synchronized interface
+    synchronized_input = nixnet.FrameInStreamSession(interface1)
+    synchronized_output = nixnet.FrameOutStreamSession(interface1)
+
+    #Set session and interface properties such as termination
+    #Note that interface properties only need to be set once per interface
+    synchronized_input.intf.baud_rate = 125000
+    synchronized_input.intf.can_term = constants.CanTerm.ON
+
+    #Connect the start trigger terminals for the synchronized interface
+    synchronized_input.connect_terminals(nixnet._cconsts.NX_TERM_FRONT_PANEL0, nixnet._cconsts.NX_TERM_START_TRIGGER)
+
+    #Start the synchronized sessions as session only
+    synchronized_input.start()
+    synchronized_output.start()
+
+    #Create the session objects for the synchronizing interface
+    synchronizing_input = nixnet.FrameInStreamSession(interface2)
+    synchronizing_output = nixnet.FrameOutStreamSession(interface2)
+
+    #Set session and interface properties such as termination
+    #Note that interface properties only need to be set once per interface
+    synchronizing_input.intf.baud_rate = 125000
+    synchronizing_input.intf.can_term = constants.CanTerm.ON
+    synchronizing_input.intf.echo_tx = True
+
+    #Connect the start trigger terminals for the synchronized interface
+    synchronizing_input.connect_terminals(nixnet._cconsts.NX_TERM_START_TRIGGER, nixnet._cconsts.NX_TERM_FRONT_PANEL1)
+
+    #Starting the synchronizing sessions will trigger the start of the synchronized sessions
+    synchronizing_input.start(constants.StartStopScope.SESSION_ONLY)
+    synchronizing_output.start()
+
+    #Request values to transmit
+    user_value = six.moves.input('Enter payload [int, int]: ')
+    try:
+        payload_list = [int(x.strip()) for x in user_value.split(",")]
+    except ValueError:
+        payload_list = [2, 4, 8, 16]
+        print('Unrecognized input ({}). Setting data buffer to {}'.format(user_value, payload_list))
+
+    id = types.CanIdentifier(1)
+    payload = bytearray(payload_list)
+    frame = types.CanFrame(id, constants.FrameType.CAN_DATA, payload)
+
+    print('The same values should be received. Press q to quit')
+    i = 0
+    while True:
+        #Apply the user input to the frame payload
+        for index, byte in enumerate(payload):
+            payload[index] = byte + i
+            
+        frame.payload = payload
+        #Write the specified frame
+        synchronizing_output.frames.write([frame])
+        print('Sent frame with ID {} payload: {}'.format(id, payload))
+        
+        #Read frames back from both input sessions
+        framesToRead = 1
+        rxTimestamp = 0
+        echoTimestamp = 0
+        receivedFrames = synchronized_input.frames.read(framesToRead)
+        echoedFrames = synchronizing_input.frames.read(framesToRead)
+        for frame in receivedFrames:
+            rxTimestamp = frame.timestamp
+            print('Received frame: {}'.format(frame))            
+            print('    payload={}'.format(list(six.iterbytes(frame.payload))))
+
+        for frame in echoedFrames:
+            echoTimestamp = frame.timestamp
+            print('Echoed frame: {}'.format(frame))            
+            print('    payload={}'.format(list(six.iterbytes(frame.payload))))
+
+        #Calculate the delta between timestamps
+        deltaT = echoTimestamp -rxTimestamp
+        print('The delta between received timestamp and echo is: {}', deltaT)
+
+        i += 1
+        if max(payload) + i > 0xFF:
+            i = 0
+        inp = six.moves.input('Hit enter to continue (q to quit): ')
+        if inp.lower() == 'q':
+            break
+    print('Data acquisition stopped.')
+
+
+if __name__ == '__main__':
+    main()