melonHD is a video converter module I designed based around Lontium Semiconductor's LT6711A. It accepts an HDMI 2.0 input signal (up to 2160p) and outputs USB-C DisplayPort 1.2 Alt Mode.

melonHD's purpose is to enable easy USB-C video output in any portable that has HDMI output. Here's a stock, unmodified Wii, with a Wii2HDMI connected to the melonHD carrier board, connected to a Dell portable USB-C monitor.
The castellated module is easy to solder to a carrier board, so anyone can easily integrate it into their portables. I've released a carrier board reference design that follows best practices.

Feature List

melonHD is powered by the downstream-facing port. This can be a little confusing if you're unfamiliar with the USB-C protocol. Basically, your USB-C monitor needs to be able to provide power to melonHD, while melonHD sends it video data. Most DP Alt Mode sinks support this mode of operation.
The reason melonHD works this way is so it can request power to charge your portable's batteries while your portable is docked. This is identical to how a Nintendo Switch works. Please see the diagram for a more detailed breakdown.
One key feature of melonHD is the customized LT6711A firmware, which allows the user to select what VBUS voltage the module requests from the downstream-facing port. Based on how you pinstrap the module, you can request 5V/3A, 9V/3A, 12V/3A, or 15V/3A. This lets you charge your portable's batteries quickly without sacrificing DP Alt Mode output. Of course, whether you can get higher voltages depends on the capabilities of the downstream port you connect to.
Also, the melonHD module has an "HPD" output pin. This pin is low when melonHD negotiates for a power-only contract, such as when you plug a charger into the USB-C port. But when you plug in a USB-C monitor, melonHD will negotiate a DP Alt Mode contract and the HPD pin will go high. This is useful for enabling GCVideo DVI only when a USB-C monitor is connected, and not when a charger is connected. You could also use it to turn off your portable's screen when an external display is connected, just like a Nintendo Switch.
How Do I Get It?!
Unfortunately, the melonHD module itself is not open source and never will be, due to legal limitations. The GitHub repository contains documentation, usage guidelines (coming soon), and an open source carrier board reference design.
In the near future, I will manufacture a small run of melonHD modules and sell them to the community. I'll bump this thread when that happens.


melonHD's purpose is to enable easy USB-C video output in any portable that has HDMI output. Here's a stock, unmodified Wii, with a Wii2HDMI connected to the melonHD carrier board, connected to a Dell portable USB-C monitor.
The castellated module is easy to solder to a carrier board, so anyone can easily integrate it into their portables. I've released a carrier board reference design that follows best practices.

Feature List
- Super compact 17 x 13mm 0.8mm-thick castellated PCB
- 480p - 2160p HDMI 2.0 input and USB-C DP 1.2 Alt Mode output
- Pin-strappable VBUS PDO selection: 5V/3A, 9V/3A, 12V/3A, or 15V/3A
- Powered directly from 5V - 15V VBUS with onboard voltage regulators
- HPD (hotplug detect) output pin

melonHD is powered by the downstream-facing port. This can be a little confusing if you're unfamiliar with the USB-C protocol. Basically, your USB-C monitor needs to be able to provide power to melonHD, while melonHD sends it video data. Most DP Alt Mode sinks support this mode of operation.
The reason melonHD works this way is so it can request power to charge your portable's batteries while your portable is docked. This is identical to how a Nintendo Switch works. Please see the diagram for a more detailed breakdown.
One key feature of melonHD is the customized LT6711A firmware, which allows the user to select what VBUS voltage the module requests from the downstream-facing port. Based on how you pinstrap the module, you can request 5V/3A, 9V/3A, 12V/3A, or 15V/3A. This lets you charge your portable's batteries quickly without sacrificing DP Alt Mode output. Of course, whether you can get higher voltages depends on the capabilities of the downstream port you connect to.
Also, the melonHD module has an "HPD" output pin. This pin is low when melonHD negotiates for a power-only contract, such as when you plug a charger into the USB-C port. But when you plug in a USB-C monitor, melonHD will negotiate a DP Alt Mode contract and the HPD pin will go high. This is useful for enabling GCVideo DVI only when a USB-C monitor is connected, and not when a charger is connected. You could also use it to turn off your portable's screen when an external display is connected, just like a Nintendo Switch.
How Do I Get It?!
Unfortunately, the melonHD module itself is not open source and never will be, due to legal limitations. The GitHub repository contains documentation, usage guidelines (coming soon), and an open source carrier board reference design.
In the near future, I will manufacture a small run of melonHD modules and sell them to the community. I'll bump this thread when that happens.