Cyclone IV 8080 CPU

When I have successfully (re-constructed) the 8080 CPU on  MAX10000 it should be straightforward to build the same functionality into CycloneIV.  We can use project stages from MAX1000 build and amend the project for CycloneIV pins and hardware components.[October 2019]

Stage 1
Create a project and use a generic verilog program (LEDwater) to check that LEDs are are setup.  The Top Level module becomes Board.v which we will use as a "PCB" for our processor.
We can then add CPU functions in the increments:
test states
Add data memory
Add ALU

Stage 2
CycloneIV provides RS232 UART for I/O.  I had an old PL23203 DB9 cable which I could plug in to the connector and PC-USB.  Unfortunately it was too old; although I persuaded it to do output I couldn't do input until I bought a new cable.
It was then straightforward to implement keyboard input and screen output via a Putty terminal emulation session.

Stage 3
In addition to the DB9 UART CycloneIV allows terminal communication via USB for a NIOS console and this same feature worked fine for my 2nd MAX1000 serial interface. I wasn't able to get the inbuilt port to work on CycloneIV so I added an FTDI RS232 interface for the serial port.  Once the corresponding CPU verilog functions had been added I had a working CycloneIV 8080 development environment complete with program load capabilities.