USB-IF

USB Interface

Interface Chip

The interface chip used on the RBL_nRF51822 board is Freescale MK20 and it provides an USB port for uploading host firmware to the target chip (i.e. the nRF51822 SoC).

New Interface Firmwre - DAPLink

ARM mbed has changed the interface firmware from CMSIS-DAP to DAPLink, it has all features as the CMSIS-DAP. Note that for the DAPLINK, the drag-and-drop drive is called DAPLINK instead of MBED.

Updating Interface Firmware

In case you have changed the USB interface firmware inside the MK20 interface chip and want to restore to default one or upgrade to lastest version, follow the steps below:

1. Press and hold the reset button on your nRF51822 board

2. Connect it to an USB port of your PC

3. Release the button and the LED will keep flashing (slowly)

4. Follow the following to update the firmware

   4.1 For Windows, just drag the firmware (DAPLink_MK20_RBL_nRF51822.bin) to the MSD drive (e.g. E:), labelled 'BOOTLOADER'

   4.2 For Linux or Mac OSX (10.9.x), use the follow command from the Terminal:

    Usage:
    $ dd if=src_firmware.bin of=/Volumes/BOOTLOADER/dst_firmware.bin conv=notrunc
   
    Example:
    $ dd if=DAPLink_MK20_RBL_nRF51822.bin of=/Volumes/BOOTLOADER/DAPLink_MK20_RBL_nRF51822.bin conv=notrunc
   

   4.3 For Mac OSX (10.10.x / 10.11.x or above):

    sudo mount -u -w -o sync /Volumes/BOOTLOADER; cp -X ~/Desktop/DAPLink_MK20_RBL_nRF51822.bin /Volumes/BOOTLOADER/
   

5. After that, the LED should keep flashing (very fast this time)

6. Remove the board from the USB port

7. Reconnect it to the USB port, your OS will show a drive labelled 'DAPLINK'

8. Now, you can drag the test firmware to the DAPLink drive to test.

9. Note that the DAPLink will not reset the target chip by default, press the RESET button to allow the target to run the uploaded firmware, you can change this by sending MSD commands to the DAPLink drive, for the details about the DAPLink automation, please refer to the MSD Commands.