RE: SPI timeout when calling from ISR

Glen M — Mon, 05 Dec 2022 19:26:14 GMT

I've hit this same issue but this discussion doesn't offer any advice on what you should do instead.

So for anyone else stumbling across this post, I've fixed it on my project by using an application work queue to get my SPI reads done as quickly as possible after exiting the ISR. My ISR just calls k_work_submit_to_queue to kick off my function that performs the SPI reads.

Good video describing work queues here:

www.youtube.com/watch

Another devzone thread with a chunk of code you can copy and use to create your own work queue (currently it's the bottom post in the discussion) here:

devzone.nordicsemi.com/.../388632

You could also probably use the system work queue, but making an application queue lets me set the priority.

RE: SPI timeout when calling from ISR

Albrecht Markus Schellenberger — Fri, 12 Aug 2022 11:40:53 GMT

Hello Ethan,

[quote user=""]When spi_write is called during the execution of an ISR it always results in an error code of 116 which implies the SPI writing is timing out. Is there something that I am missing about using SPI in interrupts?[/quote]

Referring to chapter Offloading ISR Work in the Zephyr documentation.

You are not supposed to call time/resource-consuming processes from any ISR. The Peripheral APIs go definitely under this umbrella.

Cheers,

Markus