Functions of the LXA TAC

The LXA TAC serves as an interface between the IT infrastructure on the one side and the DUT on the other side:

The LXA TAC is controlled and powered via Ethernet. Apart from Ethernet, there is only a power supply for the DUT needed. This makes the LXA TAC the perfect labgrid exporter for the desk.

The LXA TAC provides the following features to remotely control a DUT:

• Switching the power supply of the DUT, including current and voltage measurement (up to 48 V / 5 A).
• 3.3 V UART to connect to the console of the DUT. (Level converters for RS-232 or 2.5 V / 1.8 V UART are available separately.)
• Two potential-free outputs for switching boot modes or simulating key presses.
• Three USB ports for extensions such as the USB-SD-Mux, Webcams or logic analyzers.
• CAN interface for CAN 2.0 or CAN-FD communication with the DUT.
• Separate Ethernet port for the DUT.
• USB device connection for implementing USB-gadgets to the DUT.

Even more details about the device can be found in the Datasheet.

Advantages of the LXA TAC

The LXA TAC has been created based on the experience of operating a heterogeneous embedded lab with over 120 DUTs at Pengutronix. The device therefore has many advantages over a simple, makeshift exporter. Listing them all would go beyond the scope here; so here are a few examples:

• The UART power supply and the UART logic signals can be completely deactivated. In this way, leakage currents that can prevent power cycling on particularly energy-saving DUTs can be prevented.
• The potential-free outputs include a voltage measurement. This means you can get feedback about the switching process even without direct access to the device.
• The power supply to the USB ports can be switched individually. This means misbehaving USB devices can be restarted remotely.
• The Linux system on the LXA TAC contains scripts that make setting up USB-gadgets easy.

In addition, the LXA TAC comes with an IOBus-interface. IOBus is a robust expansion interface that can be used to connect additional IOs or real-time measuring devices.

As a user interface, in addition to the intuitive LEDs, there is a display with buttons, as well as a modern web interface available.

As a commercially available device, the LXA TAC has, of course, been tested according to relevant EMC standards.

For easy integration, Runner for Github Actions and Gitlab Workflows are available on the LXA TAC. This means that the LXA TAC can be directly integrated into existing workflows. In the following video, Leonard shows how to continuously testing a BSP with Gitlab Workflows and the LXA TAC can be set up:

Software

The LXA TAC software follows our open source philosophy: All software components are open source! By using Yocto and its layering feature, it is possible to create your own BSP based on meta-lxatac and to still benefit from the regular updates from Linux Automation GmbH.

Of course, Linux runs on the LXA TAC itself. A login via SSH on the device is exactly one of the use cases. Just like starting a container with a normal Linux distribution.

Availability

The LXA TAC is now available in the Linux Automation Shop. As accessories there are various power supplies, but also RS-232 and UART level shifters available.