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USB Type-C functional testing board


The USB Type-C functional testing board, Plankton Raiden board, enables USB Type-C automated functional testing.

Plankton Raiden board is a multi-layer designed testing board to switch out USB Type-C input data lane. There are several USB muxes and a DisplayPort (DP) re-driver with multiple IO ports so that we can switch USB Type-C functions with huge flexibility. On the board there is also an STM MCU chip for muxes and switches controller, and FTDI listener to get commands from the outside host.

Hardware Capabilities



  • DUT as host: USB 3.1 Gen 1
  • DUT as device: USB 2.0


  • USB-C to DisplayPort converter
  • Includes DP redriver to allow 4K @ 60Hz


  • Source 5V/12V/20V@3A for DUT as sink
  • Monitor voltage/current on VBUS for DUT as source

CC monitoring

  • Dual CC connection allows “flip connector” tests
  • USB PD traffic monitor on both CC lines

Block diagram


For schematic and board files, please see the attached zip file at the bottom of this page.

Hardware Switches

Set the switches to default setting before flashing EEPROM or firmware.

SW9 - Enable Debug buttons (switch to DISABLE to enable function, there is a
layout mistake)

SW1 - Set Boot0 signal to low (No MCU_BOOT0)

SW3 - Set to L:CN3 or CN5

SW14 - Set to L: CN5 to HUB

In the following session, please power up the board and connect to the host through USB3.0 Micro B port (CN5).

EEPROM Programming

For a brand-new board, please program its EEPROM first for setting serial number and product and vendor ID.

Install ftx-prog, you can download the program from the Github here and unzip to your home directory.

sudo apt-get install build-essential gcc make libftdi-dev
cd ~/ftx-prog-master

and then use this command to flash EEPROM. The format of serial number is "901008-XXXXX", get the last 5 digits from the back of the Plankton Raiden board.


sudo ftx_prog --old-vid 0x0403 --new-vid 0x18d1 --old-pid 0x6015 --new-pid 0x500c --new-serial-number <serial number> --cbus 0 GPIO --cbus 1 Tristate --cbus 2 GPIO --cbus 3 GPIO --manufacturer "Google Inc" --product "Plankton" --ftprog-strings

Firmware Source Code

The firmware is located In the Chromium Embedded Controller repository under board/plankton/ :

Building Firmware

Within your ChromiumOS chroot, the syntax is:

cd ~/trunk/src/platform/ec
make BOARD=plankton

Firmware image will be located under build/plankton/ec.bin

If your chroot tree is newly-built, you may encounter an error while "make BOARD=plankton"

Try to type this command first:


~/trunk/src/scripts/setup_board --board=peach_pit --nousepkg

### and then try "make BOARD=plankton" again.

### Running Servod

1. Build up local package of servod

cd ~/trunk/src/third_party/hdctools
cros_workon --host start dev-util/hdctools
sudo emerge hdctools
  1. Run servod for Plankton Raiden board
sudo servod -p 0x500c

Flashing Firmware

  1. Open another terminal (you need to leave servod on): Note: use "cros_sdk --no-ns-pid" to enter chroot, otherwise you will get error while flashing firmware.
cd ~/trunk/src/platform/ec
  1. Flash firmware which you built earlier into Plankton Raiden (get port number in servod message, 9999 in normal):
./util/flash_ec --board=plankton --port=<port number>

You may also assign the image file to flash into Plankton Raiden by the --image argument:

./util/flash_ec --board=plankton --port=<port number> --image=<your/image/file/path>

Debug Buttons and LEDs

If debug buttons are enabled (SW9), you can use buttons to switch board functions. LEDs are helpful for monitoring current state of Plankton Raiden.

image image
SW6 Source 20 V/3A to Type-C port (while DUT plugs on) DS8, DS4, and DS9 will be on
SW12 Source 12 V/3A to Type-C port (while DUT plugs on) DS8 and DS9 will be on
SW11 Source 5V/3A to Type-C port (while DUT plugs on) DS9 will be on
SW8 Provide power from VBUS to CN1 DS5 will be on
SW2 Reset MCU
SW5 Toggle USB3.0 & DP for USB type C port DS1 is on - USB3.0 - Debug USB from CN14 to DUT DS1 is off - DP
SW7 Enable case close debugging
SW10 Flip CC Connect DUT via CC1 -DS3 off Connect DUT via CC2 -DS3 on
Plug in type C cable Communication on CC1 DS2 will blink
Plug in type C cable Communication on CC2 DS6 will blink

Software Control

Using CLI

  1. Use modprobe to load on ftdi_sio on your Unix host.
sudo modprobe ftdi_sio
echo 18d1 500c | sudo tee /sys/bus/usb-serial/drivers/ftdi_sio/new_id
  1. Check whether TTY is established. An additional ttyUSBx will appear for ftdi_sio (if not, you may need to remove and attach PR board again).
ls /dev/ttyUSB*
  1. Open the command-line interface by Unix console tools (ex. socat, cu).
cu -l /dev/ttyUSBx -s 115200

Please refer to the document "Plankton Raiden MCU command table" below for CLI.

Using dut-control

  1. Inside chroot, open up servod with ftdi_sio on PR board.
sudo servod -p 0x500c
  1. Use “dut-control” to get all available components of PR board.