nRF52840 DK v1.0.0

IF Boot/Reset button

The nRF52840 Development Kit (DK) board is equipped with an IF Boot/Reset button (SW5).

This button is connected to the interface MCU on the board and has two functions: During normal operation the button will function as a reset button for the nRF52840 SoC. For this to work, pin reset on P0.18 needs to be enabled in the SoC.

The button is also used to enter the bootloader mode of the interface MCU. To enter the bootloader mode, keep the reset button pressed while powering up the board until LED5 starts to blink. You can power up the board either by disconnecting and reconnecting the USB cable or by toggling the power switch (SW8).

Note: Pin reset can be enabled by adding the CONFIG_GPIO_AS_PINRESET variable to the compiler preprocessor macros. The way of doing this depends on the Integrated Development Environment (IDE)/toolchain in use:

If your program does not enable pin reset, this functionality can also be enabled on an already programmed device by calling nrfjprog.exe with argument --pinresetenable. To disable pinreset again, reprogram with --chiperase.