How to offload work of IRQ_ZERO_LATENCY interrupt ?

[Nicolas Brunner]

I'm using a SPI with a circular buffer so i need to have an interrupt with low latency that reset the RXD.PTR when the buffer is full.

The SPI is used for communicating with an ADC so the transfer can't be delayed.

Without using the IRQ_ZERO_LATENCY flag, the RXD.PTR reset happens sometime too late.

But when I'm using the IRQ_ZERO_LATENCY flag, I'm unable to offload the ADC data works because the call to k_sem_give() is not allowed with IRQ_ZERO_LATENCY.

Is there a way to offload an interrupt with the IRQ_ZERO_LATENCY flag ?

[JONATHAN LL]

Hi Nicolas,

Is there a way to offload an interrupt with the IRQ_ZERO_LATENCY flag ?

 No. 

You have to find a different way. setting a variabel or GPIO trigger might be a solution. 

Regards,
Jonathan

[Nicolas Brunner]

Thank you the information.

My solution is to enable another IRQ (in my case it's the timer that generate the start of SPI transfer) from my zero latency IRQ. The other IRQ interoperate with the kernel and disable his own IRQ.