Gary Cho

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5 years, 6 months ago.

Delaying interrupt handling during lengthy SPI read from flash

Hi everyone,

I am using an external SPI flash chip for logging purposes. Occasionally it needs to run queries on this log and this will cause lengthy SPI flash read to last from a few seconds to minutes. To ensure responsiveness to other events, I would pause this SPI flash read every 10 ms to check if an interrupt has occurred.

My question is if I do this

Loop_until_end_of_query { 1) _disable_irq() 2) do 10 ms of SPI flash read 3) _enable_irq() }

Would an interrupt that happened during the 10ms, where the interrupt is disabled, be serviced immediately after _enable_irfq() call?

Thank you in advanced to taking time to reply.

Gary Cho

1 Answer

Zoltan Hudak
5 years, 6 months ago.

Hello Gary,

I think those interrupts will never be serviced. So rather than disabling interrupts I would suggest to perform the queries in another thread (running in parallel with the data aquisition thread). In that case scheduling will be done automatically by mbed-os. Moreover, in that thread you can use an event queue to carry out the queries so interrupts will always have higher priority.