This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

Google Dragonclaw Development Board


Dragonclaw is a board created by Google for fingerprint-related functionality development. See the Dragonclaw Schematics [1] for board schematics, layout and BOM.

Board has connectors for fingerprint sensors. Console is exposed over μServo connector. MCU can be flashed using μServo or SWD.


  • STM32F412CGU6 UFQFPN48 package

Peripherial Mapping

  • USART_1 TX/RX : PA9/PA10

  • USART_2 TX/RX : PA2/PA3


  • SPI_2 CS/CLK/MISO/MOSI : PB12/PB13/PB14/PB15

Programming and Debugging

Build application as usual for the dragonclaw board, and flash using μServo or an external J-Link connected to J4. If μServo is used, please follow the Chromium EC Flashing Documentation [2].


Use SWD with a J-Link or ST-Link. Remember that SW2 must be set to CORESIGHT.