Here is some previews of Multicomp VHDL I'm currently porting and testing. Here a Z80 system running MP/M 2.1 (a multi-user time-sharing OS for the Z80 CPU):

...and here a session using a simple sketch for the STM32 to use it as a serial-USB bridge attached to a VHDL serial port on the FPGA:

In this way it is possible use The Thing with only the USB cable, connecting it to a terminal emulator on a PC:

Here MP/M 2.1 with two concurrent users, one connected to the local VDU/Keyb and the other connected with a VHDL serial port "redirected" to the STM32 serial on USB (using the UART "bridge" sketch on the STM32 and managed by a terminal emulator on a PC):

And here playing Gorilla:

Stay tuned...