Benjamin Cabé

Zephyr Weekly Update – Zephyr 2.7.5 LTS is out

Benjamin Cabé
Zephyr Weekly Update - June 2, 2023

Zephyr Weekly Update - June 2, 2023

Like I mentioned last week, the release of Zephyr 3.4 is approaching (currently scheduled for June, 16), and the first release candidate is already out. There are slightly less noteworthy highlights this week, since last week’s post was published only a couple hours before the actual feature freeze deadline. So, since it should be a short read, I thought I would also take some time to list 3 things you can do to help make 3.4 a success!

This week in Zephyr land

Zephyr v2.7.5 LTS is out!

Chris Friedt from Meta, our release engineer for this LTS (Long-Term Support) version, just pushed the big button yesterday, and Zephyr v2.7.5 LTS is officially out the door. I will let you go through the release notes to catch up on the issues that have been addressed, but I would like to call your attention to the changes made around mbedTLS:

Moving mbedTLS to 2.28.x series (2.28.3 precisely). This is an LTS release that will be supported with bug fixes and security fixes until the end of 2024.

Detailed information can be found in: https://github.com/Mbed-TLS/mbedtls/releases/tag/v2.28.3 https://github.com/zephyrproject-rtos/zephyr/issues/56071.

This version is incompatible with TF-M and because of this TF-M is no longer supported in Zephyr LTS. If TF-M is required it can be manually added back changing the mbedTLS revision on west.yaml to the previous one (5765cb7f75a9973ae9232d438e361a9d7bbc49e7). This should be carefully assessed by a security expert to ensure that the know vulnerabilities in that version don’t affect the product.

Notable changes in the 3.4 main branch

Like I said, this one will be short (or is it?), but some nice changes nevertheless. In a slightly less structured way as usual, here goes:

Testing

Should Read Version From Shell
    Prepare Machine
    Start Emulation
    Wait For Prompt On Uart   uart:~$
    Write Line To Uart        version
    Wait For Line On Uart     Zephyr version

Display improvements

Example of a 20×4 character LCD display.

Auxiliary Displays are text-based displays that have simple interfaces for displaying textual, numeric or alphanumeric data […] auxiliary displays do not support custom graphical output to displays (and and most often monochrome), the most advanced custom feature supported is generation of custom characters.
These inexpensive displays are commonly found with various configurations and sizes, a common display size is 16 characters by 2 lines.

As always, a good way to get started with this new functionality is to check out to the dedicated code sample. You will certainly note that the API couldn’t be more straightforward!

snprintk(data, sizeof(data), "Hello world from %s", CONFIG_BOARD);
rc = auxdisplay_write(dev, data, strlen(data));

Sensors

Drivers

Miscellaneous

Help with 3.4 release

Test, test, test!

Please take 3.4 RC1 for a spin! In particular, if you already plan on moving your product development to 3.4, then now is the perfect time to start doing so. All features are essentially in, and the RC1 is essentially very similar to what the final release will be, minus perhaps some outstanding bugs or regressions that you can contribute to help catching. Please report any issue directly in the project’s GitHub issue tracker.

Review the documentation

This one can be particularly interesting if you’ve never actually contributed back to Zephyr, and were maybe scared of doing so for you never had any code to contribute. I cannot stress enough that contributing to improving the documentation (including trivial fixes such as correcting typos!), is immensely valuable too, and not every contribution has to be code!

If you end up giving some of the new (or older) features a try, make sure to send pull requests should you catch mistakes in the documentation, things that could be explained better, etc.

On that note, we have an ongoing documentation survey that should take you just 5 minutes to complete. The goal is to understand better how you (and your organization) are using the documentation today, and what are some of the things you’d potentially like to see improved.

Take the Zephyr RTOS Technical Documentation Survey

Help spread the word

Whether you’re directly involved with the project as a contributor or maintainer, or whether you’re just a user, I would really encourage you to think about what you could do to help spread the word when the release will come out.

One thing that I would really love to see is cool demos of Zephyr 3.4 in action. So, for example, if you’ve been helping get a new board added (dozens were contributed since 3.3!) in 3.4, why not work on a short video that would showcase Zephyr running on it? Bonus points if it also showcases some of the recently added features, of course 🙂 If this sounds like something that you would like to do, please feel free to ping me if you have some ideas or questions!

A big thank you to the 4 individuals who had their first pull request accepted this week 💙 🙌: Andrei, Göran, Kornel, and Tyler.

As always please feel free to jump in with your thoughts or questions in the comments below. See you next week!

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Catch up on all the editions of the Zephyr Weekly Update:

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