NRFICE enables dongle-free debugging with an officially licensed, built-in SEGGER JLink-OB. JLink-OB ("OB" standing for "On-Board") is a professional debugging solution running on a dedicated MCU. The JLink-OB implementation on NRFICE includes SWD debugging, a VCOM virtual COM port over USB, and target MCU flash memory downloading.

Typically, JLink-OB is designed into MCU evaluation boards by the chip maker. For instance, the nRF5340 Audio DK from Nordic Semiconductor features a JLink-OB hosted on a second nRF5340.

The NRFICE JLink-OB is similarly hosted on an ST Micro STM32F072CBU6.

Let’s see how we can configure NRFICE to operate using a single USB-C cable to provide all:

• Board power
• SWD Debugging
• VCOM communications

The power routing header allows configuration of the board power source from any of these:

• 9V-12V AC adapter
• USB-C connected to nRF5340
• USB-C connected to STM8 (JLink-OB)

In order to simultaneously power the board, debug, and communicate via the VCOM port, apply shunts to the power header as follows:

1. Connect the VUSB net to STM_USB5V to source USB power from the JLink-OB port.

2. Connect the VUSB Net to 5 V so that the five-volt net is sourced from USB, rather than the AC adapter.

With this configuration, the NRFICE board is ready for development on-the-go with no other cabling or tools needed than a single USB-C cable.

Thanks again to our supporters!

As support continues to come in during the last week of our funding campaign, we are gearing up for final checking of the production package so our orders will go out on schedule.