Sending Echo packets to check communication

This tutorial demonstrates how to use PyACI and send a simple Echo command to the connected device. The response of the Echo command will contain the same data as the data that was sent when issuing the command. You can use this command every time you connect to the target board with PyACI to verify that the serial transport layer is working as intended.

Table of contents

• Requirements
• Configuring and testing connection

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Requirements

You need at least one compatible development kit for this demonstration, flashed with the following example:

• Serial example

See Compatibility for information about the compatible development kits.

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Configuring and testing connection

After building and programming the serial example, complete the following steps:

1. Connect to the device with the interactive console:

   $ python interactive_pyaci.py -d /dev/ttyACM0 --no-logfile
   
    To control your device use d[x], type d[x]. and hit tab to see the available methods.
    x is for the device index; devices will be indexed based on the order of com ports
    given with the option -d(the first device, d[0], can also be accessed using device).
   
   Python 3.5.2 (default, Nov 17 2016, 17:05:23)
   Type 'copyright', 'credits' or 'license' for more information
   IPython 6.1.0 -- An enhanced Interactive Python. Type '?' for help.

2. Send a test Echo command to see that the device is connected:
   1. Display information about the command:

      In [1]: cmd.Echo?
      Init signature: cmd.Echo(data)
      Docstring:
      A simple loopback test command, to verify that the serial transport layer is working as
      intended.
      
      Parameters
      ----------
       data : uint8_t[254]
       Data to echo back.
      File: nrf5_sdk_for_mesh/scripts/interactive_pyaci/aci/aci_cmd.py
      Type: type

   2. Test the command:

      In [2]: send(cmd.Echo("hello world"))
      2020-03-24 12:45:18,063 - INFO - ttyACM0: {event: DeviceEchoRsp, data: {'data': 'hello world'}}

      The send function is a helper function for sending commands to the first connected device. It accepts a CommandPacket object as a parameter. All of these are imported from aci/aci_cmd.py by the interactive script.
3. Send an Echo command to the first device by addressing the device through the list of devices d, in this case d[0]:

   In [3]: d[0].send(cmd.Echo("hello world"))
   2020-03-24 12:46:36,147 - INFO - ttyACM0: {event: DeviceEchoRsp, data: {'data': 'hello world'}}

Note

You might experience the following timeout error:

2017-08-02 10:13:45,427 - INFO - ttyACM0: cmd Echo, timeout waiting for event

In this case, use one of the following options:

• Ensure that you are connected to the correct board and verify that the example is running. You can also try resetting or reconnecting the board, or both.
• Using a serial terminal emulator, try to send an Echo command raw:

  06 02 48 65 6c 6c 6f

  You should receive:

  06 82 48 65 6c 6c 6f