nRF52840 Preview DK v0.9.x

Buttons and LEDs

The four buttons and four LEDs on the nRF52840 Preview DK board are connected to dedicated GPIOs on the nRF52840 chip.

Table 1. Button and LED connection
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 GPIO P0.13P0.16 are needed elsewhere, the LEDs can be disconnected by cutting the short on SB5SB8, see figure Figure 1. Since P0.11 and P0.12 are used as a part of the Trace functionality, Button 1 and Button 2 can be moved to alternative GPIOs, see chapter Debug input and Trace for more information.

Figure 1. Disconnecting the LEDs

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, P0.25 pins must be configured as an 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.

Figure 2. Button and LED configuration