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 -d {BUILD_DIR}

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, set the XXXXX Jumper to a HIGH/LOW 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 ardep dfu --bootloader --build-dir build

  • Wait for the upgrade to complete:

    • If you can’t see the bootloader console, wait >20 seconds.

    • If you can see the output, wait for the panic! message.

  • Perform a manual power cycle. Your new firmware should be running now