Silicon Labs PyCommander (CLI version)

Introduction

This Python package wraps Simplicity Commander functionality and exposes a native Python API for interacting with Commander in your scripts.

Requirements

This package requires Python 3.10 or newer. Required PyPI packages are:

• platformdirs
• pyyaml

Additionally, Simplicity Commander requires the SEGGER J-Link drivers to be installed on your system.

Note that this package only contains the CLI version of Simplicity Commander. The GUI version is available in the silabs-pycommander-gui package.

Installation

pip install silabs-pycommander-cli

Usage

More details about Simplicity Commander and its Command Line Interface can be found in the official documentation for Simplicity Commander. The documentation is also helpful when using the Python API, as the command names and available options are the same.

Command Line Interface

From the command line, pycommander-cli is a razor-thin wrapper around the Simplicity Commander CLI; it behaves exactly like the Simplicity Commander CLI, except for the case when the options -v or --version are passed as arguments, in which case the version of the pycommander-cli package is printed in addition to the normal version information from the Simplicity Commander CLI.

pycommander-cli --help
pycommander-cli --version
pycommander-cli <command> [options]
pycommander-cli <command> <subcommand> [options]

Python API

At the lowest level, the Commander class provides all the CLI commands as methods to the class. These methods return a dictionary containing the command output, similarly to what the Simplicity Commander CLI does when the --json flag is used.

from pycommander_cli import Commander

# Instantiate the Commander class with a serial number
commander = Commander(serial_number="44055955")

# Perform the 'commander device info' command
print(commander.device.info(target_device="EFR32MG24"))

# Perform the 'commander util appinfo' command
print(commander.util.appinfo(filename="firmware.hex"))

# Perform the 'commander flash' command
print(commander.flash.flash(filenames=["firmware.hex"], address=0x08000000))

The Commander class also exposes a few standalone helpers; for example, getVersion() returns the embedded Simplicity Commander, J-Link, EMDLL and other component versions as a CommanderVersionInfo object:

from pycommander_cli import Commander

commander = Commander()

# Get the version of the embedded Simplicity Commander, J-Link, EMDLL and other components
print(commander.getVersion())

listAvailableAdapters() is a helper method that can be used to (unintrusively) scan for available adapters. This method returns a list of BasicAdapterInfo objects, each carrying jlink_serial_number, ip_address and nickname (any of which may be None):

from pycommander_cli import Commander

commander = Commander()

# List USB adapters
adapters = commander.listAvailableAdapters(list_usb_adapters=True)
for adapter in adapters:
  print(adapter.jlink_serial_number, adapter.nickname)

# List network adapters
adapters = commander.listAvailableAdapters(list_network_adapters=True)
for adapter in adapters:
  print(adapter.ip_address, adapter.nickname)

Please note that not all commands are available to the Commander class. These are typically commands that are intended for interative CLI sessions, and include command suites like vcom, vuart, rtt and swo. Moreover, some commands in the Commander class have stricter requirements for the arguments than their CLI counterparts, for the same reasons as mentioned above. For example, the aem dump command requires the outfile and duration arguments to be provided. For a more flexible approach to streaming AEM data, please see the AemStream class below.

For ad-hoc invocations of commands that are not exposed by the typed API, you can fall back to Commander.runCommand(...), which forwards arguments directly to the underlying Simplicity Commander CLI:

# Run a raw Commander CLI command and capture its output
result = commander.runCommand("rtt", "--help", json_formatted_output=False)
print(result.stdout)
print(result.stderr)

The Adapter and Target classes

pycommander-cli exposes several convenience methods for common tasks, split across two classes. These methods return different data types depending on the command. The types are available in the pycommander_core.types module.

The Adapter class handles tasks related to the adapter itself. These methods are only available on Silicon Labs adapters, and are not functional when using a generic J-Link adapter:

• Reading adapter and kit information
• Upgrading the adapter's firmware
• Resetting the adapter
• Configuring the target device's supply voltage
• Setting the adapter's VCOM configuration
• Analyzing the target device's energy usage
• +++

The Target class handles tasks related to the target device (a Silicon Labs MCU), and works with any supported debug adapter:

• Locking/unlocking the device for debug access
• Setting the CTUNE value
• Flashing firmware to the device
• Erasing the device's flash
• Configuring code regions (Series 3 only)
• +++

When instantiating the Adapter class, a Commander class instance is created and made available as an attribute of the Adapter class. If a target_device is provided to the Adapter class, a Target class instance is created and made available as an attribute of the Adapter class as well.

An Adapter class instance (with a potential Target class instance) should be used to represent a connection to a single Silicon Labs adapter (with an attached target device). Multiple Adapter class instances can be used to represent multiple adapters (with or without their respective target devices):

from pycommander_cli import Adapter

serial_numbers = ["44055955", "44055956", "44055957"]
adapters = [Adapter(serial_number=sn, target_device="EFR32MG24") for sn in serial_numbers]
for adapter in adapters:
  print(adapter.info())

A typical session against a single adapter may look like this:

from pycommander_cli import Adapter
from pycommander_core.types import AdapterInfo, AdapterVoltageInfo, VcomHandshake, CtuneValue

# Instantiate the Adapter class with a serial number and target device
adapter = Adapter(serial_number="44055955", target_device="EFR32MG24")

# Ensure we're running the latest firmware on the adapter
adapter.upgradeFirmware()

# Get the adapter information
adapter_info: AdapterInfo = adapter.info()

# Get the voltage information
voltage_info: AdapterVoltageInfo | None = adapter.getVoltage()

# Set the VCOM configuration of the adapter
adapter.setVcomConfig(115200, VcomHandshake.RTSCTS, True)

# Get the CTUNE value of the target device
ctune_value: CtuneValue = adapter.target.getCTUNE()

# Set the CTUNE value of the target device
adapter.target.setCTUNE(ctune_value.board)

A common high-level task is flashing application firmware to the target device. Target.flashApplication() accepts one or more files (.hex, .s37, .bin, .gbl or .rps) and handles the underlying flash, verify and reset steps:

from pathlib import Path
from pycommander_cli import Adapter

adapter = Adapter(serial_number="44055955", target_device="EFR32MG24")

success: bool = adapter.target.flashApplication(filenames=[Path("firmware.hex")])

The AemStream class

The AemStream class provides a pythonic way of streaming AEM measurements from a Silicon Labs adapter. The measurements are returned as AemMeasurement objects, which contain the timestamp, current, voltage, and the calculated power. An AemStream object is suitable for streaming AEM measurements from a Silicon Labs adapter, and there is no limitation to the duration of the streaming. The stream may be stopped at any time.

Like the underlying Simplicity Commander CLI, the AemStream class supports a variety of options for configuring the AEM data capture process, like setting up simple triggers to start the data capture process and specifying the data output rate.

Context Manager Syntax

When using the context manager syntax, the AemStream object is opened automatically when the context manager is entered, and a connection to the adapter is established. The connection is cleanly closed when the context manager is exited.

from pycommander_cli import AemStream
from pycommander_core.types import AemMeasurement

# Instantiate a 10 second AEM stream with a data output rate of 100 Hz
with AemStream(serial_number="44055955", datarate_hz=100, duration_s=10) as aem_stream:
  for measurement in aem_stream:
    print(measurement)

Manual Syntax

The AemStream class can also be instantiated without using the context manager syntax. In this case, the open() method must be called to open the connection to the adapter and start the data capture process, and the close() method must be called to gracefully stop the data capture process and close the connection.

from pycommander_cli import AemStream
from pycommander_core.types import AemMeasurement

# Instantiate the AemStream class with a serial number and a set data rate
aem_stream : AemStream = AemStream(serial_number="44055955", datarate_hz=100)

# Open the AEM stream
aem_stream.open()


some_condition : bool = False
# Read the AEM measurements
for measurement in aem_stream:
  # Do something
  # ...

  if some_condition:
    break

# Close the AEM stream
aem_stream.close()

Error handling

Failed Commander invocations raise typed exceptions, so your automation scripts can react to them in a structured way. Three exception classes are exposed from pycommander_core.errors:

• PyCommanderInputError — Commander rejected the arguments (return code -1 / 255).
• PyCommanderRuntimeError — Commander failed at runtime, e.g. the adapter could not be reached or the operation timed out (return code -2 / 254).
• PyCommanderError — base class for any other non-zero return code, and parent of the two above.

from pathlib import Path
from pycommander_cli import Adapter
from pycommander_core.errors import PyCommanderError, PyCommanderRuntimeError

adapter = Adapter(serial_number="44055955", target_device="EFR32MG24")

try:
  adapter.target.flashApplication(filenames=[Path("firmware.hex")])
except PyCommanderRuntimeError as e:
  print(f"Commander failed at runtime: {e}")
except PyCommanderError as e:
  print(f"Other Commander error: {e}")

Logging

All Commander invocations can be logged to a file by passing the log_file_path argument to the Commander constructor. Each invocation is recorded with a timestamp, which is handy when diagnosing issues in long-running automations or production-test rigs.

from pathlib import Path
from pycommander_cli import Adapter, Commander

# Build a Commander with logging enabled, then attach it to an Adapter
commander = Commander(serial_number="44055955", log_file_path=Path("pycommander.log"))
adapter = Adapter(commander=commander, target_device="EFR32MG24")