Herring 6502 is a modular computer system I built based on the WDC 65C02 CPU and related parts. Currently, I have boards for CPU, memory (RAM or ROM), serial port, GPIO, clock/decoder, and bus monitor. All of the components were chosen to be 3.3v compatible. This lets me interface more easily with modern components like FPGAs or microcontrollers.
The software is a simple monitor/bootloader program that runs from ROM. It allows code to be loaded over the serial port into RAM and then executed. This removes the need to constantly flash ROM images. I have cc65 configs and shell scripts to assist with this process.
The primary user interface is the serial port to a host PC. The next milestone is running Herring as a standalone system with a keyboard or controller and VGA output.