Install logisim-evolution from the github repo
After installation open logisim-evolution, open the circuit file
Use the instruction set reference to create programs in RAM
To change instruction sets you can load another microcode rom into the microcode rom inside the cpu subcircuit
To attach more devices to the device bus you can just add a comparator comparing the portaddr line to the device address and use buffer gates to set the bus lines when the device is selected
16 bit addressing
8 bit opcodes
Up to 16 microcode steps
83 implemented opcodes