Bootloader¶
Building the bootloader¶
The bootloader can be build with:
west ardep build-bootloader
The first line of the output gives you the expanded west build command.
Flashing the bootloader¶
The bootloader is flashed with an external debug probe (e.g. J-Link) using the west flash command.
For this connect the SWD Pins of the ARDEP board to the debug probe an run:
west flash
The Pinout of the SWD connector is printed on the boards backside.
See the board.cmake file under boards/arm/ardep for more info about supported debuggers.
Bootloader mode¶
In this mode, the ardep board does not load any firmware and waits for a firmware upgrade via the dfu-util tool.
This is handy if your firmware is broken and you can’t update it from there.
It is helpful to see the Bootloader console output on UART-A for this.
Entering Bootloader mode¶
To enter the bootloader mode, pull the PE4 pin (labeld BOOT) to a LOW (setting the jumper) state while power-cycling or pushing the Reset button.
When the red led light up permanently, the board is in bootloader mode.
On UART-A you will see the following output:
*** Booting Zephyr OS build zephyr-vx.y.z ***
I: Starting bootloader
I: Waiting for USB DFU
Upgrading the firmware¶
Build the firmware you want to flash (assuming it is in the build directory)
Perform the upgrade with
west flashWait for the upgrade to complete