Pi-Cast KVM Switch

This week we received the adapter board so that the KVM switch could be easily stacked on top of the Pi-Cast. The adapter board also supports PoE ethernet and a fan for the Pi-Cast.

 In the prev design, we use the gpio to control the switch, but in the new version we've added another control method call serial control, you can control the switch by the USB-to-Serial port. The control protocol is compatible with the EZCOO.

I just received the new design PCB. After assembly and some fly wires job, everything works fine.

And I got a comment from Louis S. He said that if I choose the RJ45 port as the IO port that someone may plug it into the network equipment which may cause the device damage especially when the RJ45 port was plugged into which supports PoE.

So I decided to follow the original  PiKVM Hat design and placed the optocoupler between the GPIO and the RJ45 port. This change means that the RJ45 port no longer transceivers the USB signal, we will still need 3 cable features all function.

The change for the fly wires job and place optocoupler for signal isolation will be present in the next version PCB.

Adding an MCU to control the KVM switch is one of the Todo lists. This weekend I just finish the concept by wiring up all the stuff with an MCU EVT board. The MCU I choose is CH32V003F4P6( a 32-bit RISC-V MCU running at 48MHz, more detail here). 

With the help of the MCU, the KVM switch can be controlled by the PiKVM web UI or the manual switch button, the web UI can also indicate which pc is active in the meantime. In the next version, I'll add 2 LEDs on the PCB to indicate the active PC too.

The PCB file that combines the KVM switch and the MCU into one PCB board was finished. Hopefully, I will get the PCB from the factory next week. I'll post an update at that time.