Linking Zephyr logging to UART powerdown

RE: Linking Zephyr logging to UART powerdown

hugzy123 — Tue, 21 Jan 2025 13:03:07 GMT

Thank you Kenneth this worked

RE: Linking Zephyr logging to UART powerdown

Kenneth — Mon, 20 Jan 2025 10:03:24 GMT

Hello,

Old case, but can you try something like:

&uart0{ disable-rx; }

Kenneth

RE: Linking Zephyr logging to UART powerdown

hugzy123 — Fri, 17 Jan 2025 12:07:22 GMT

Hi Kenneth ,

Do you know if anything like this has been implemented for zephyr yet?

We're also looking for a way to disable UART in sleep when logs are not needed to save power.

Thanks,

RE: Linking Zephyr logging to UART powerdown

Kenneth — Thu, 08 Dec 2022 14:25:06 GMT

I made an internal jira to look into this for future. Sorry that I can't do anything more. You may to contact the zephyr community also on this topic: https://docs.zephyrproject.org/latest/introduction/index.html#resources Nice if you updated the case if you find this is already possible.

Kenneth

RE: Linking Zephyr logging to UART powerdown

allard.p — Thu, 08 Dec 2022 08:24:00 GMT

It would be a nice feature for a next release.

I don't want to edit something in my nrf connect/zephyr repository, so I guess I need to copy shell_log_backend.c to my project, and then need to do some CMake magic to override the file? Could you provide an example on how to do this?

RE: Linking Zephyr logging to UART powerdown

Kenneth — Wed, 07 Dec 2022 16:04:04 GMT

Hi again,

I tried looking at the uart log backend, and I could not find that there is any good way to implement what you want. So I don't see any other way than to for instance "hack" the log_backend_uart.c such that you for instance do a resume when entering char_out() and suspend before you return.

Best regards,
Kenneth

RE: Linking Zephyr logging to UART powerdown

allard.p — Wed, 07 Dec 2022 07:54:30 GMT

I'm using the latest stable release (NCS 2.1.2). If the system waits for all logs to leave the UART it would be handy to get a callback before the system decides to got to sleep, and when the system wakes up again. In these callbacks the UART would be enabled/disabled.

I did try something like this in attempt four: registering two callbacks with pm_notifier_register. But these callbacks never get called, does Nordic use a custom implementation?

RE: Linking Zephyr logging to UART powerdown

Kenneth — Tue, 06 Dec 2022 22:03:45 GMT

Hello,

You are not stating which ncs version you are using, I think there may have been changes in the power management, and I was under the impression that the system should not go to sleep if there was any logs to process. However, if this is not handled, would checking log_buffered_cnt() before trying to disable UART help?

Kenneth