Program your Nordic Semiconductor nRF51 or nRF52 board using the Arduino IDE.

Does not require a custom bootloader on the device.

modification https://github.com/sandeepmistry/arduino-nRF5/

1. Download Zadig
2. Plugin Segger J-Link or DK board
3. Start Zadig
4. Select Options -> List All Devices
5. Plug and unplug your device to find what changes, and select the Interface 2 from the device dropdown
6. Click Replace Driver

NOTE: To roll back to the original driver go to: Device Manager -> Right click on device -> Check box for "Delete the driver software for this device" and click Uninstall

1. Download .inf file drivers from blacksphere github
2. Plugin Black Magic Probe
3. Point the installer to the folder containing blackmagic.inf

NOTE: If using Windows 10 or Linux then two UART COM ports will be visible without requiring additional drivers

If the selected board has an external 32 kHz crystal connected, it will be used as the source for the low frequency clock. Otherwise the internal 32 kHz RC oscillator will be used. The low frequency clock is used by the delay(ms) and millis() Arduino API's.

The Generic nRF51 and nRF52 board options have an additional menu item under Tools -> Low Frequency Clock that allows you to select the low frequency clock source. However, Nordic does not recommend the Synthesized clock, which also has a significant power impact.