Use NFC pin (GPIO 0.9, 0.10, 0.12) as other purpose such as RTC input

RE: Use NFC pin (GPIO 0.9, 0.10, 0.12) as other purpose such as RTC input

Simonr — Thu, 25 Jan 2024 12:24:02 GMT

If there are no HW on the board that can draw the current, I assume it is the GPIOTE peripheral that is left running for example until you call the nrf_gpiote_int_disable() which will let the nRF52 go into a low power mode (10µA). I'm not sure I see how this is related with your initial question. I suggest you check out this blog by my colleague Scott on all the most common ways to reduce current consumption if you need lower current consumption, and generally optimizing your power consumption.

Best regards,

Simon

RE: Use NFC pin (GPIO 0.9, 0.10, 0.12) as other purpose such as RTC input

simon.jonghun.song — Wed, 24 Jan 2024 01:55:23 GMT

Hi Simonr,

The current consumption was 230 uA before applying nrf_gpiote_int_disable().

After applying nrf_gpiote_int_disable(), it shows 10 uA consumption.

In this case, there's HW circuit diagram exist for RTC in the PCB board but don't have parts attached on PCB board.

So I wasn't sure that why it is draining much power as parts not attached.

RE: Use NFC pin (GPIO 0.9, 0.10, 0.12) as other purpose such as RTC input

Simonr — Tue, 23 Jan 2024 13:52:02 GMT

I'm not sure I understand what you mean here. How much does the nrf_gpiote_int_disable() lower the current exactly? It makes sense that it lowers the current consumption as you disable the RTC and GPIOTE. To use these pins as GPIOs on the nRF52832 you have to add the following preprocessor define CONFIG_NFCT_PINS_AS_GPIOS (add under project settings -> "Preprocessor" -> "Preprocessor definitions") in SEGGER Embedded Studios.

Best regards,

Simon

RE: Use NFC pin (GPIO 0.9, 0.10, 0.12) as other purpose such as RTC input

simon.jonghun.song — Mon, 22 Jan 2024 23:26:41 GMT

Hi Simonr,

Thank you for reply. I checked it.

I had a confusion due to different module chip(nrf52811, nrf52832 with same pin to pin mapping) on the same PCB.

I find the solution but I don't understand.

I changed code and it is used during initialization.

nrf_gpio_cfg_output(RTC_SCK);nrf_gpio_pin_set(RTC_SCK);

nrf_gpio_cfg_output(RTC_IO);nrf_gpio_pin_set(RTC_IO);

nrf_gpio_cfg_output(RTC_CE);nrf_gpio_pin_set(RTC_CE);

==>

nrf_gpiote_int_disable(RTC_SCK);

nrf_gpiote_int_disable(RTC_IO);

nrf_gpiote_int_disable(RTC_CE);

And the power consumption drops as similar as board #1.

As you stated, P0.09, P0.10, P0.12 are general GPIO.

But why nrf_gpiote_int_disable() drops current? Currently, there is no part attached for RTC on the PCB.

And I need to use nrf52832 also,

Will the DCONFIG_NFCT_PINS_AS_GPIOS flag added to Makefile OK for drop current?
In this case I also don't use NFC and want to use it as GPIO (RTC input)

RE: Use NFC pin (GPIO 0.9, 0.10, 0.12) as other purpose such as RTC input

Simonr — Mon, 22 Jan 2024 13:53:38 GMT

The reason you see this compile error is because the nRF52811 doesn't have an NFC tag peripheral, so NFCPINS won't be recognized. In the pin assignments section of the nRF52811 PS you can see that P0.09 and P0.10 are only stated as GPIOs, so there is no need for this config in nRF52811 based projects.

Best regards,

Simon