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Interface MCU
The Interface MCU is used to control the firmware on the nRF52832 IC by the on-board SEGGER J-Link.
Figure 2: Interface MCU
5.1 IF Boot/Reset button
The nRF52 Preview Development Kit board is equipped with a boot/reset button (
SW5
).
This button is connected to the Interface MCU on the board and has two functions:
• Resetting the nRF52832 device.
• Entering bootloader mode of the interface MCU.
During normal operation the button will function as a reset button for the nRF52832 device. For this
to work, pin reset on P0.21 needs to be enabled for the nRF52832 device. The button is also used to
enter the bootloader mode of the Interface MCU. To enter bootloader mode, keep the reset button
pressed while powering up the board until LED (
LD5
) starts to blink. You can power up the board either by
disconnecting and reconnecting the USB cable, or toggle the power switch (
SW6
).
Important:
Pin reset can be enabled by defining the CONFIG_GPIO_AS_PINRESET variable
in the project settings. This can be done by defining the preprocessor symbol in Keil, go to:
Project > Options for Target > C/C++ > Preprocessor Symbols > Define
. Here you can add the
CONFIG_GPIO_AS_PINRESET variable after NRF52.
This functionality can be removed by doing a nRFjprog --recover.
5.2 Virtual COM port
The on-board Interface MCU features a Virtual COM port via UART.
The virtual COM port has the following features:
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