How do I properly configure the GPIO for pins 0, 1, 9, 10, 11, and 21 on the nRF52-DK?

[AuFries]

I would like to use the oscillator pins (if possible), NFC pins, and pin 11/21 as GPIO. I can see why 0,1,9,10 would not work but I am confused why 11 and 21 do not. Every other GPIO (except UART stuff) works fine.

21 is dully on at all times as above and 11 is not on or responsive at all. 

For NFC pins, CONFIG_NFCT_PINS_AS_GPIOS=y does not work by itself.

For the oscillator pins I tried,

CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

and that does not work. (Is this functionality even possible with the dev kit?)

Below is the code i'm using attempting to blink the LED with these GPIO:

	mux_gpio_dev = device_get_binding("GPIO_0");
    gpio_pin_configure(mux_gpio_dev, 10, GPIO_OUTPUT | GPIO_ACTIVE_HIGH);
	gpio_pin_configure(mux_gpio_dev, 9, GPIO_OUTPUT | GPIO_ACTIVE_HIGH);
	gpio_pin_configure(mux_gpio_dev, 21, GPIO_OUTPUT | GPIO_ACTIVE_HIGH);
	gpio_pin_configure(mux_gpio_dev, 11, GPIO_OUTPUT | GPIO_ACTIVE_HIGH);
	gpio_pin_configure(mux_gpio_dev, 0, GPIO_OUTPUT | GPIO_ACTIVE_HIGH);
	gpio_pin_configure(mux_gpio_dev, 1, GPIO_OUTPUT | GPIO_ACTIVE_HIGH);

	for(;;) {
		gpio_pin_set(mux_gpio_dev, 10, 1);
		gpio_pin_set(mux_gpio_dev, 9, 1);
		gpio_pin_set(mux_gpio_dev, 21, 1);
		gpio_pin_set(mux_gpio_dev, 11, 1);
		gpio_pin_set(mux_gpio_dev, 0, 1);
		gpio_pin_set(mux_gpio_dev, 1, 1);
		k_sleep(K_MSEC(500));
		gpio_pin_set(mux_gpio_dev, 10, 0);
		gpio_pin_set(mux_gpio_dev, 9, 0);
		gpio_pin_set(mux_gpio_dev, 21, 0);
		gpio_pin_set(mux_gpio_dev, 11, 0);
		gpio_pin_set(mux_gpio_dev, 0, 0);
		gpio_pin_set(mux_gpio_dev, 1, 0);
		k_sleep(K_MSEC(500));
	}

[Håkon Alseth]

Hi,

 

CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

and that does not work. (Is this functionality even possible with the dev kit?)

P0.00 and P0.01 is physically connected to the LF XTAL, so they need to be altered in both firmware and on the DK itself:

https://infocenter.nordicsemi.com/topic/ug_nrf52832_dk/UG/dk/hw_32khz_crystal.html?cp=5_2_4_3_5

 

This also applies to the P0.09 and P0.10, which are the NFC pins.

You need to add this to your project:

CONFIG_NFCT_PINS_AS_GPIOS=y

And on the DK you need to do a similar operation as for the LF clk GPIOs:

https://infocenter.nordicsemi.com/topic/ug_nrf52832_dk/UG/dk/hw_nfc_if.html?cp=5_2_4_3_8

 

P0.21 is nRESET. This can be used as a GPIO as well, by adding:

CONFIG_GPIO_AS_PINRESET=n

 

Although, I would recommend that you just use other unused GPIOs if you have the option do to so.

 

Kind regards,

Håkon

[AuFries]

I tried CONFIG_GPIO_AS_PINRESET=n in prj.conf then tried blinking 21 on two separate kits and it's still not functional. Ideas on this? Is there a different configuration than other GPIO? Also, pin 11 is not functional on both kits. What does Arduino D0 on the silkscreen mean?

[Håkon Alseth]

Hi,

 

You'll need to solder SB43 to route the P0.21 to the pin header:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fug_nrf52832_dk%2FUG%2Fdk%2Fhw_nfc_if.html&cp=5_2_4_3_8

 

Again, I would strongly recommend that you use any other available GPIOs on the nRF52-DK instead of the ones that you have already chosen.

AuFries said:

What does Arduino D0 on the silkscreen mean?

It conforms to the arduino form factor. D0 is P0.11 on the nRF52-DK.

 

Kind regards,

Håkon