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The USB Type-C to DP Adapter connects a USB Type-C plug to a DP receptacle. It enables users of any Chrome device that implements USB-Type C to connect to a DisplayPort display.
This adapter is an implementation of a USB Type-C to DisplayPort Cable. It follows the requirements described in Section 3.2 “Scenarios 2a and 2b USB Type-C to DisplayPort Cables” of the VESA DisplayPort Alt Mode for USB Type-C Standard. The design is similar to the description in Appendix A.2 of the Standard and shown in Figure A-2: DisplayPort Video Adaptor Cable Block Diagram.
It provides the following features:
For schematics, click here or see the attached file.
The firmware is located In the Chromium Embedded Controller repository under board/dingdong/ :
https://chromium.googlesource.com/chromiumos/platform/ec/+/master/board/dingdong/
Within your Chromium OS chroot, the syntax is:
cd ~/trunk/src/platform/ec make BOARD=dingdong
The firmware is normally flashed via the kernel, as part of the Chrome OS Auto-Update process. Payloads are located in /lib/firmware/cros-pd
.
When the adapter is connected to a Chrome device, you can manually flash the read-write firmware as follows:
ectool --cros_pd flashpd 3 <port> /tmp/dingdong.ec.RW.bin
The device must be in developer mode to run the ectool
command. After running this command, the firmware is located in ~/trunk/src/platform/ec/build/dingdong/ec.bin .
Developers of devices based on this design may need to install an initial image by putting the STM32F072 into DFU mode. This can be done by asserting PD_BOOOT0 (TP8 in the schematic) and resetting the MCU. It can be helpful to attach a switch for this purpose on prototype devices.
Installing an image requires the dfu-util tools package on the Chrome device where the adapter is connected. To deploy dfu-util and copy the chromeos-ec image from within your Chromium OS chroot, the syntax is:
where board-name is the name of the Chrome device, for example peppy, and host-IP-address is its IP address on the network.
The next step is to connect the adapter to the Chrome device in DFU mode and write a full image (RO + RW). On the Chrome device, the syntax is:
flash_ec --board=dingdong --image=/tmp/ec.bin
810-10117-02: Initial release. 810-10117-03: Power sequencing and timing improvements.