nrf52833 + PPI + PWM Pulse Counter

RE: nrf52833 + PPI + PWM Pulse Counter

John — Thu, 10 Nov 2022 08:09:05 GMT

Thank you. It compiles now

RE: nrf52833 + PPI + PWM Pulse Counter

Sigurd — Tue, 08 Nov 2022 19:11:43 GMT

Hi,

I took a quick look. Try replacing the places where NRFX_TIMER_DEFAULT_CONFIG_IRQ_PRIORITY is used with IRQ_PRIO_LOWEST

RE: nrf52833 + PPI + PWM Pulse Counter

John — Tue, 08 Nov 2022 18:41:50 GMT

Hi, I've downloaded your sample code. I'm using V1.9.1 of nRF Connect, unfortuantely it doesn't compile.

I'd be gratefuil if you would be kind enough to take a look for me please.

RE: nrf52833 + PPI + PWM Pulse Counter

Sigurd — Wed, 10 Aug 2022 11:37:36 GMT

[quote user="hmolesworth"]What's "a bit"? One might assume that the HFCLK isn't doing much on the Timer as "In counter mode, the TIMER's internal Counter register is incremented by one each time the COUNT task is triggered, meaning the timer frequency and the prescaler are not utilized in counter mode". I don't see figures for PPI, which presumably also requires HFCLK ..[/quote]

GPIOTE -> PPI -> TIMER draws power, I would have to double check to be sure, but if I recall correctly it's a 1.1uC charge when its "wakes" up to increment the counter register.

RE: nrf52833 + PPI + PWM Pulse Counter

Sigurd — Wed, 10 Aug 2022 11:26:32 GMT

[quote user="harshal034"]One follow up question: To save the power if we disable the PPI channel, it should stop counting and consuming that extra power, right? Basically, we would like to enable/disable this PPI at runtime. To make sure that we have it only when we need it.[/quote]

Correct.

RE: nrf52833 + PPI + PWM Pulse Counter

hmolesworth — Thu, 04 Aug 2022 22:03:03 GMT

What's "a bit"? One might assume that the HFCLK isn't doing much on the Timer as "In counter mode, the TIMER's internal Counter register is incremented by one each time the COUNT task is triggered, meaning the timer frequency and the prescaler are not utilized in counter mode". I don't see figures for PPI, which presumably also requires HFCLK ..

RE: nrf52833 + PPI + PWM Pulse Counter

embeddedER — Thu, 04 Aug 2022 21:10:42 GMT

Thanks Sigurd for the prompt response.

We will look into the example you shared.

One follow up question: To save the power if we disable the PPI channel, it should stop counting and consuming that extra power, right? Basically, we would like to enable/disable this PPI at runtime. To make sure that we have it only when we need it.

RE: nrf52833 + PPI + PWM Pulse Counter

Sigurd — Thu, 04 Aug 2022 21:03:13 GMT

Hi,

[quote userid="112081" url="~/f/nordic-q-a/90707/nrf52833-ppi-pwm-pulse-counter"]Is it possible to do such counting, without interrupt and CPU cycles?[/quote]

Yes, I have some sample code that showcases this here: https://github.com/sigurdnev/ncs-playground/blob/master/samples/pulse_detector/src/main.c

[quote userid="112081" url="~/f/nordic-q-a/90707/nrf52833-ppi-pwm-pulse-counter"]Since ours is a battery operated device, does using PPI affect sleep current? Currently we have measured sleep current as 2.7uA with our custom HW.[/quote]

Yes, when the TIMER Counter increases because of the PWM pulse the current will go a bit up.