Count slow pulses, most power friendly way

RE: Count slow pulses, most power friendly way

davidlr — Wed, 05 Dec 2018 23:46:20 GMT

You are right Hakon. Your help is very appreciated.

Problem was Anomaly 89. After adding the workaround code inside my TWI uninit function all is working as expected. As you said, 20uA extra drawn by the IN_EVENT and I got around 20uA average in sleep ON with your code too. What a nightmare!

Thank you man, you rock!

RE: Count slow pulses, most power friendly way

Håkon Alseth — Wed, 05 Dec 2018 15:35:30 GMT

Enabling IN_EVENT will give a bit of higher consumption (~20 uA), per this errata:

High current consumption in System ON Idle mode

But it should not use 0.5 mA.

Did you run the example I posted standalone (based on $SDK/examples/peripherals/gpiote)? I get approx. 20 uA of sleep current with it on my nRF52-DK. If you keep the input pin active, you'll see an added ~250 uA (from the pull resistor).

Kind regards,

Håkon

RE: Count slow pulses, most power friendly way

davidlr — Wed, 05 Dec 2018 14:52:08 GMT

RTC can't be used as counter as per documentation. Only possible source is LF clock.

RE: Count slow pulses, most power friendly way

davidlr — Wed, 05 Dec 2018 13:04:33 GMT

Thanks, I am trying RTC.

RE: Count slow pulses, most power friendly way

davidlr — Wed, 05 Dec 2018 13:00:01 GMT

Thanks for your kind reply Håkon.

After enabling timer nrfx_timer_enable(&m_timer) power consumption jumps from 40uA to 500uA.

Also I understand from documentation that NRFX_GPIOTE_CONFIG_IN_SENSE_HITOLO(true) with TRUE value enables IN_EVENT so the high frequency clock is requested (and more power drawn).

RE: Count slow pulses, most power friendly way

Håkon Alseth — Tue, 20 Nov 2018 13:32:05 GMT

Hi,

When a TIMER is in COUNT mode, it will be low power.

Here's an example, based on yours, that consumes very little in sleep mode (just toggles a LED every "AMOUNT_OF_PULSES" detected).

devzone.nordicsemi.com/.../main.c

Your initial example uses the PORT event, and will then trigger if you have any other buttons configured with the PORT event as well, so I changed it to use GPIOTE->IN instead.

If you want to count the amount of pulses from an external source within a given time-frame, you could just comment out the call to "nrfx_timer_compare" + the second PPI channel and run a TASKS_CAPTURE[0] in a app_timer instance.

Kind regards,

Håkon

RE: Count slow pulses, most power friendly way

AmbystomaLabs — Mon, 19 Nov 2018 17:55:44 GMT

If you run the main timer hf clock is always on by default.

Use the rtc timer instead. The rtc clock always runs and depending on which clock source you use is less than 3 microamp.