ESP interrupt latency

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Joined: Sun Jul 12, 2015 1:57 pm

Re: ESP interrupt latency

Postby uwwint » Sun Jul 12, 2015 4:07 pm

Hi there,

I am trying to acheive exactly the same keeping the SPI stream as constant as possible. Was this in the End resolved? And what was the SPI configuration used?


Posts: 12
Joined: Tue Oct 25, 2016 3:57 pm

Re: ESP interrupt latency

Postby roc2 » Thu Dec 15, 2016 7:30 pm

mculibrk wrote:Any information about the latency of peripheral (HSPI) interrupts related to the ETS_SPI_INTR_ATTACH(); API function?

Or what is the interrupt latency in general for the ESP?

cross posted here:

Best regards,

Hi, mculibrk!
Is your problem solved, and how to solve the problem of interrupt latency? I have the same question when use gpio interrupt :? :? :? ..

Posts: 22
Joined: Mon Feb 09, 2015 3:35 am

Re: ESP interrupt latency

Postby mculibrk » Thu Dec 29, 2016 3:39 pm

I'm really sorry for this laaaaate reply...

anyway, regarding int latency...
I was able to solve (kind of) the irq latency of the SPI... this was done by setting an "undocumented" (in newer versions of the header files) register of the SPI. I don't recall the exact one but I can find and post if you really need it.
But, this is specific to SPI... it is a kind of "intercharacter delay" value which is by default set to something. When this value is set to 0 the response is much, much better.

I did not try/tested the latency of the GPIO irq... and I really doubt that there will be a similar register to "tweak" to get faster response.

What numbers are you seeing? What's the gpio irq latency you observed?
Are you using irqs directly or by some API/default handler?


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