Subj : Re: Pi Pico and Zephyr RTOS
To   : Brian Gregory
From : The Natural Philosopher
Date : Sun Jan 12 2025 20:33:03

On 12/01/2025 18:45, Brian Gregory wrote:
> On 25/12/2024 10:02, mm0fmf wrote:
>> On 25/12/2024 00:30, wmartin wrote:
>>> On 12/24/24 12:47, mm0fmf wrote:
>>>> Has anyone used the Zephyr RTOS on a Pi Pico or any other smallish
>>>> system?
>>>>
>>>> I'm writing something relatively simple for a Pico in C using the
>>>> SDK. It doesn't need an RTOS, the old classic cyclic executive
>>>> paradigm will work fine.
>>>> At one time I'd have used an 8bit CPU but why faff about when you
>>>> can get something like a Pico for hardly any cost even if 2x Cortex
>>>> M0+ seems overkill.
>>> Well, you can have two threads, kinda, with the Pico without an
>>> RTOS...just split your work between the two cores. I just did a
>>> simple project using one core to do a com link to a pc for
>>> command/response, and the other core to do a real-time hardware
>>> controller chore. Made it painless...
>>
>> That was my plan. The project has to do simple things like scan a 4x4
>> keyboard, light assorted LEDs and send strings over the UART at 38k4
>> to control something. I'd already decided that I would run all the
>> UART send/receive on one core and run the control on the other core.
>> That way the control core remains non-blocking and the UART core can
>> block if needed.
>
> Doesn't the PICO SDK include some FreeRTOS examples?

It does. If You cant live without a pre-emptive multtaskking solution

>
> Do you really need Zephr RTOS rather than FreeRTOS?
>
> Note though, that I'm not sure if the examples have the ability to use
> both cores yet, I remember that initially they just allowed
> multi-threading using a single core on the PICO.
>
> If it was me I think I might just write my own RTOS that worked the same
> way I was originally taught to do multi-threading (using Dykstra's
> semaphores and not much else) rather than having to learn and understand
> how somebody else thought it should be done.
>
+1 for that.

--
I would rather have questions that cannot be answered...
....than to have answers that cannot be questioned

Richard Feynman

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