GPIOTE won't sleep after first button press drawing too much current

RE: GPIOTE won't sleep after first button press drawing too much current

Kenneth — Wed, 30 Oct 2019 18:52:23 GMT

Yes.

RE: GPIOTE won't sleep after first button press drawing too much current

Fabio — Wed, 30 Oct 2019 13:11:00 GMT

ok, I will try that. To make sure my math is right, if I do this it will consume I = U /R = 2.6 / 1000 = 2.6ua?

RE: GPIOTE won't sleep after first button press drawing too much current

Kenneth — Wed, 30 Oct 2019 12:59:02 GMT

You have enabled internal pull up (in_configlow.pull = NRF_GPIO_PIN_PULLUP;), if you expect customers will be pushing this button for a long period of time, I instead suggest use an external pull-up of 1Mohm instead.

RE: GPIOTE won't sleep after first button press drawing too much current

Fabio — Wed, 30 Oct 2019 12:51:32 GMT

if you are right, does that mean that by pulling a pin low I cannot physically simply create a button with a battery that lasts 2 years? If I can have a current pull of 30ua or less I can. So creating a button operated by battery with less than 200ua is impossible? Unless I reduce the input voltage? If I reduce the input voltage to 1.7v then I = U / R = I = 1.7 * 13 = 100ua. So impossible to have a simple button that consumes less than 100ua?

RE: GPIOTE won't sleep after first button press drawing too much current

Kenneth — Wed, 30 Oct 2019 09:41:58 GMT

I was thinking that 200uA could be close to the current through a pull-up resistor that is pulled low: U = R * I = ~13kohm * ~200uA = ~2.6V (which I expect is close to VDD on the board?).

RE: GPIOTE won't sleep after first button press drawing too much current

Fabio — Fri, 25 Oct 2019 04:07:48 GMT

is it possible that I have a faulty power profiler? Can someone tell me what do you get when you run this code in the DK?

RE: GPIOTE won't sleep after first button press drawing too much current

Fabio — Fri, 25 Oct 2019 03:03:58 GMT

- _WFE only: 6.6ua

- add input pin sense, see that it wakeup and measure current - wakes up. 7ua. When button clicked 200ua

- add pin handler callback, see that it wakeup and measure current - 7ua. When button clicked 200ua

- add output pins, see that it wakeup and measure current - 25ua. When button clicked 200ua

No matter what I do, as soon as I press the button it spikes up to 200ua. Something is very wrong. What do you get if you run this code?

RE: GPIOTE won't sleep after first button press drawing too much current

Kenneth — Thu, 24 Oct 2019 12:09:31 GMT

In cases like this my suggestion is to simplify the code.

Do you get the intended current with _WFE() only
->add input pin sense, see that it wakeup and measure current
->add pin handler callback, see that it wakeup and measure current
->add output pins, see that it wakeup and measure current
->add system off, see that it reset on wakeup and measure current

Kenneth

RE: GPIOTE won't sleep after first button press drawing too much current

Fabio — Thu, 24 Oct 2019 02:17:15 GMT

If you run this code in a nrf52840 DK do you get different results?

RE: GPIOTE won't sleep after first button press drawing too much current

Fabio — Thu, 24 Oct 2019 01:48:30 GMT

I removed the NRF_POWER->SYSTEMOFF = 1; and added the 10ms delay. In addition, I am using the buttons of the DK board which in my understanding have a pull up resistor which I am activating with the in_configlow.pull = NRF_GPIO_PIN_PULLUP; line. Would this cause it to NOT be floating?

Having done all of this, I STILL get 200ua+ on the first button press. This happens with 2 DKs. I can't possibly imagine that I have 2 defective DK boards?

What else can I do? Nothing seems to bring this down.

RE: GPIOTE won't sleep after first button press drawing too much current

Kenneth — Wed, 23 Oct 2019 14:25:17 GMT

The NRF_POWER->SYSTEMOFF = 1; seems a bit odd, since it will go to system OFF, which means the chip will reset on wakeup. I would have placed some 10ms delay and led toggling in beginning of main() just to make sure you have control over what state it is in. This should also make it easier to measure in your power profiler.

That said, make sure you have full control over the logic level on your input pin, since a floating input pin may draw anything from 30-200uA (or more), in other word connect it to GND or VDD though a pull-resistor or similiar, not leve it unconnected.

Also, 30uA is also too high if you are only doing _WFE() and some GPIO's, is it possible that you are sourcing any current through the output pin (e.g. driving any LED or similar).