The four buttons and four LEDs on the nRF52840 DK are connected to dedicated GPIOs on the nRF52840 System on Chip (SoC).
| Part | GPIO | GPIO alternative | Solder bridge |
|---|---|---|---|
| Button 1 | P0.11 | P1.07 | - |
| Button 2 | P0.12 | P1.08 | - |
| Button 3 | P0.24 | - | |
| Button 4 | P0.25 | - | |
| LED 1 | P0.13 | SB5 | |
| LED 2 | P0.14 | SB6 | |
| LED 3 | P0.15 | SB7 | |
| LED 4 | P0.16 | SB8 |
If P0.13–P0.16 are needed elsewhere, the LEDs can be disconnected by cutting the short on SB5–SB8. See Disconnecting the LEDs for more information.
Since P0.11 and P0.12 are used as part of the Trace functionality, Button 1 and Button 2 can be moved to alternative GPIOs. See Debug input and trace for more information.
The buttons are active low, meaning that the input will be connected to ground when the button is activated. The buttons have no external pull-up resistor, and therefore, to use the buttons, the P0.11, P0.12, P0.24, and P0.25 pins must be configured as input with an internal pull-up resistor.
The LEDs are active low, meaning that writing a logical zero (0) to the output pin will illuminate the LED.
