The Arm Mbed OS Pigweed Example demonstrates the usage of Pigweed module functionalities in an application.

You can use this example as a reference for creating your own application.

The example is based on Matter and Arm Mbed OS, and supports remote access and control of device over a serial port.

Pigweed functionalities are integrated into this application. The Remote Procedure Call (RPC) server is created. It allows sending commands through the serial port to the device. The following RPC protocols services are available:

• Echo - receive message and send the same payload back

• Overview
• Run application
  • Environment setup
  • Building
  • Flashing
  • Debugging
  • Testing
    • Serial port terminal
    • RPC console
  • Supported devices
    • Notes
• Device UI
  • Notes

Overview

Pigweed libraries are built and organized in a way that enables faster and more reliable development. In the Matter project, the Pigweed module is planned to be used to create system infrastructures, for example for performing on-device tests, but considering its general functionalities, it can be useful also in other cases.

Run application

Environment setup

Before building the example, check out the Matter repository and sync submodules using the following command:

$ git submodule update --init

Building the example application requires the use of ARM Mbed-OS sources and the arm-none-gnu-eabi toolchain.

The Cypress OpenOCD package is required for flashing purpose. Install the Cypress OpenOCD and set env var OPENOCD_PATH before calling the flashing script.

cd ~
wget https://github.com/Infineon/openocd/releases/download/release-v4.3.0/openocd-4.3.0.1746-linux.tar.gz
tar xzvf openocd-4.3.0.1746-linux.tar.gz
export OPENOCD_PATH=$HOME/openocd

Some additional packages may be needed, depending on selected build target and its requirements.

The VSCode devcontainer has these components pre-installed. Using the VSCode devcontainer is the recommended way to interact with Arm Mbed-OS port of the Matter Project.

Please read this README.md for more information about using VSCode in container.

To initialize the development environment, download all registered sub-modules and activate the environment:

$ source ./scripts/bootstrap.sh
$ source ./scripts/activate.sh

If packages are already installed then you just need to activate the development environment:

$ source ./scripts/activate.sh

Building

The Pigweed application can be built in the same way as any other Matter example ported to the mbed-os platform.

• by using generic vscode task:

Command Palette (F1) => Run Task... => Run Mbed Application => build => pigweed-app => (board name) => (build profile) => (build type)

• by calling explicitly building script:

${MATTER_ROOT}/scripts/examples/mbed_example.sh -c=build -a=pigweed-app -b=<board name> -p=<build profile> -T=<build type>

Both approaches are limited to supported evaluation boards which are listed in Supported devices paragraph.

Mbed OS defines three building profiles: develop, debug and release. For more details please visit ARM Mbed OS build profiles.

There are also three types of built application: simple, boot and upgrade:

• simple - standalone application, mainly for developing and testing purpose (all building profiles are supported)
• boot - signed application + bootloader, it supports booting process and can be use for firmware update (only release building profiles is supported)
• update - signed application, application image can be used for firmware update (only release building profiles is supported)

When using the building script, it is possible expand the list of acceptable targets; this may be useful for rapid testing of a new mbed-targets.

Flashing

The Pigweed application can be flashed in the same way as any other Matter example ported to mbed-os platform.

The Open On-Chip Debugger is used to upload a binary image and reset the device.

• by using VSCode task:

Command Palette (F1) => Run Task... -> Run Mbed Application => flash => pigweed-app => (board name) => (build profile)

• by calling explicitly building script:

${MATTER_ROOT}/scripts/examples/mbed_example.sh -c=flash -a=pigweed-app -b=<board name> -p=<build profile>

• by using VSCode launch task:

Run and Debug (Ctrl+Shift+D) => Flash Mbed examples => Start Debugging (F5) => (board name) => pigweed-app => (build profile)

The last option uses the Open On-Chip Debugger to open and manage the gdb-server session. Then gdb-client (arm-none-eabi-gdb) upload binary image and reset device.

It is possible to connect to an external gdb-server session by using specific ‘Flash Mbed examples [remote]’ task.

Debugging

Debugging can be performed in the same was as with any other Matter example ported to mbed-os platform.

The Open On-Chip Debugger is used to to open and manage the gdb-server session. Then gdb-client (arm-none-eabi-gdb) connect the server to upload binary image and control debugging.

Run and Debug (Ctrl+Shift+D) => Debug Mbed examples => Start Debugging (F5) => (board name) => pigweed-app => (build profile)

It is possible to connect to an external gdb-server session by using specific ‘Debug Mbed examples [remote]’ task.

Testing

Serial port terminal

The application traces are streaming to serial output. To start communication open a terminal session and connect to the serial port of the device. You can use mbed-tools for this purpose (mbed-tools):

mbed-tools sterm -p /dev/ttyACM0 -b 115200 -e off

After device reset these lines should be visible:

[INFO][CHIP]: [-]Mbed pigweed-app example application start
...
[INFO][CHIP]: [-]Mbed pigweed-app example application run

The pigweed-app application launched correctly and you can follow traces in the terminal.

RPC console

The RPC console is an interactive Python shell console, where the different RPC command can be invoked. It is a complete solution for interacting with hardware devices using pw_rpc over a pw_hdlc transport. For more details about Pigweed modules visit Pigweed modules.

Building and installing

To build and install the RPC console check the guide CHIP RPC console.

Run

To start the RPC console run the following command and provide device connection parameters as arguments:

• --device/-d the serial port to use.
• --baudrate/-b the baud rate to use.
• --output/-o the file to which to write device output (HDLC channel 1), provide - or omit for stdout.
• --socket-addr/-s alternatively use socket to connect to server, type default for localhost:33000, or manually input the server address:port.

Example:

chip-console -d /dev/ttyUSB0 -b 115200 -o /tmp/pw_rpc.out

To send the echo message type the following command, where you define the message content:

In [1]: rpcs.pw.rpc.EchoService.Echo(msg="Hello device")

The response from the device should be:

Out[1]: (Status.OK, pw.rpc.EchoMessage(msg="Hello device"))

For more details about RPC console and supported services visit CHIP RPC console.

Supported devices

The example supports building and running on the following mbed-enabled devices:

Notes

• More details and guidelines about porting new hardware into the Matter project with Mbed OS can be found in MbedNewTarget
• Some useful information about HW platform specific settings can be found in pigweed-app/mbed/mbed_app.json.
  Information about this file syntax and its meaning in mbed-os project can be found here: Mbed-Os configuration system)

Device UI

This section lists the User Interface elements that you can use to control and monitor the state of the device. These correspond to PCB components on the platform image.

USER LED shows the overall state of the device. The following states are possible:

• Solid On — The application was flashed and run successfully.

Notes

Some of the supported boards may not have sufficient number PCB components to follow above description. In that case please refer to Supported devices section and check board's ‘Platform components’ column for additional information about the limitation.