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Overview

We have two types of OpenSK, V1 and V2. They have almost same schematic but different casing.
Currently, only V2 is available to the market.


OpenSK V2

OpenSK V1

It has a metal housing with only one button in the aft area.

NOTE

The LED and User button are together. The button material is transparent, so user can see LED light through the button.
Since the LED is behind the button, you have to check it from the aft area to find it breathing or flashing.

1. Switch To bootloader mode

After user connects the device to a computer, push and hold on the user button for more than 10 seconds and then release the button. If the red LED is breathing, OpenSK is in bootloader mode.

2. LED status

LED behavior Mode type Trigger Method
Red LED is breathing bootloader mode Connect OpenSK to USB port, press the user button for more than more than 10 seconds and then release the button
Red LED is flashing bootloader mode Flash the firmware
No LED on Working mode Idle
R/G/B LED is flashing Working mode Wait for user presence when receiving FIDO command

3. Hardware

The hardware schematic and PCB are shared here.


OpenSK V1

OpenSK V1

It has a 3D-printed case with one user button and one RESET button.

1. Switch To bootloader mode

After connecting OpenSK to the USB port, please insert a paper clip or a SIM-eject tool to the RESET button hole to switch it to bootloader mode. This is similar to user pushes the RESET button on the original nRF52840 USB dongle.

NOTE

The RESET button hole is covered by OpenSK label. So if you want to program the firmware occasionally, you can choose not to cover the label although we send the label to you together with OpenSK hardware.

2. LED status

LED behavior Mode type Trigger Method
Blue LED is breathing bootloader mode Use a paper clip or a SIM-eject tool to push RESET button in RESET button hole
Blue LED is flashing bootloader mode Flashing the firmware
No LED on Working mode Idle
R/G/B LED is flashing Working mode Wait for user presence when receiving FIDO command

3. Hardware

The hardware schematic and PCB files can be downloaded here.

Check Bootloader Mode

Sometimes, maybe you don't know whether your OpenSK is in bootloader mode after above operation, you can have three ways to check.

1. LED breathing

If the red LED is breathing, OpenSK is in bootloader mode, this is the simplest way.

2. lsusb command

On Linux or macOS, just run

$ lsusb
to see the result.
(Plesae make sure you have this command installed previously.)

If there is line similar to below message(1915:521f & Nordic & Open DFU Bootloader)

Bus 020 Device 026: ID 1915:521f Nordic Semiconductor ASA Open DFU Bootloader  Serial: FFCCAE942A17
then it is in bootloader mode. Other message line without Open DFU Bootloader but include 1915:521f and Nordic means it is in normal working mode.

3. USB Prober.app

On macOS, if you have USB Prober.app installed, run this app. If you have OpenSK attached and it is in bootloader mode, you should find USB information similar to below picture.

OpenSK bootloader mode
This means it is in bootloader mode.