One of the biggest challenges early on in firmware development was 1.6 support (there is no datasheet for the proprietary Xcalibur encoder). We used a homebrew app to cycle through all possible video modes with a logic analyzer hooked up the SMBus interface. Worth noting there are over 100 modes!

Final notes about the 4-pin OpenXHD port - JP5 is a 1.25mm vertical through hole picoblade connector - traces are electrically isolated from the rest of the board - traces were designed to have a roughly 75Ω impedance for analog video signals - the 3.5mm port, 4 pin and S/PDIF LED are all optional

Early in the design process we wanted more I/O on OpenXHD. A 3.5mm jack and TOSlink port would not fit next to the HDMI port, so we started with a combo 3.5mm TRS/Mini TOSlink port. That was quickly replaced with a 3.5mm TRRS jack and a red LED firing at the back end of it for mini TOSlink S/PDIF.

Early in the project we decided to migrate from Ryzee119's 20 pin flex cable design, to the standard 24 pin connection the community was already using. This is from mid 2024 using a very early flex cable with overly thick and too densely packed traces causing pixel bus crosstalk. < HDMI | YPbPr >

After many iterations and testing we have settled on a 12mm riser above the AV port screw mounts for users who want to install OpenXHD and keep their AV port. These and other 3D models will be available for free when OpenXHD releases. The "Sidequest Prototype" flexes are for an upcoming project...

Preview boards and installation kits are being prepared and sent out to firmware developers and testers.