Best way to measure time between falling/rising edges (NCS, Zephyr, NRF52840)

RE: Best way to measure time between falling/rising edges (NCS, Zephyr, NRF52840)

Domi471 — Thu, 02 Nov 2023 13:58:14 GMT

Thank you, have a super nice day too! 🙂

RE: Best way to measure time between falling/rising edges (NCS, Zephyr, NRF52840)

Håkon Alseth — Thu, 02 Nov 2023 13:46:55 GMT

Hi Dom,

Glad to hear that the sample was helpful!

Hope you have a wonderful day!

Kind regards,

Håkon

RE: Best way to measure time between falling/rising edges (NCS, Zephyr, NRF52840)

Domi471 — Thu, 02 Nov 2023 12:00:24 GMT

Thank you very very much for your extensive answer, that helps a lot :).

Kind regards,

Dom

RE: Best way to measure time between falling/rising edges (NCS, Zephyr, NRF52840)

Håkon Alseth — Wed, 18 Oct 2023 10:53:38 GMT

Hi,

[quote user=""]is there a safe way to measure the time between rising and falling edges (accuracy +-1µs, duration of the pulses are 50µs or more) on a GPIO(TE) pin? If so, can you please show me?[/quote]

Yes, it is possible to do this with:

* 2 * GPIOTE IN channels (one for rising, one for falling)

* TIMER CC

* PPI channels

Since two GPIOTE channels are required here, you should route your signal to two GPIOs.

The algorithm would look something like this:

* Configure GPIOTE ch #1 as IN low-to-high (ie. rising)

* Configure GPIOTE ch #2 as IN high-to-low (ie. falling)

* Setup TIMER in 16M resolution

* Use PPI to start timer on rising edge

* Use PPI to capture and stop timer on falling edge

Now you can read the CC register and get the value in 16M units. Remember to clear the nrfx timer instance on each read.

Here's an example of such a setup:

devzone.nordicsemi.com/.../timed_5F00_signals_5F00_ncs240.zip

Kind regards,

Håkon