Features
Features
64k memory
8-bit data bus, 16-bit address bus, dedicated hardware IO bus
ALU with add, subtract, AND, OR, XOR, inc/dec, bit-shift
Programming Panel to key values into memory
Serial UART at 115,200 baud
Breadboard vs PCB
From the start I've decided I will not limit myself to a breadboard only build.
While I do prefer the aesthetic of breadboards, I'll use custom designed PCBs when it makes more sense to do so.
Once a single register has been prototyped and works, there is nothing to learn by wiring 16 identical ones on breadboards.
Segmentation
I want a clear segmentation between each "classic" component of a computer.
CPU, Memory, Storage, Input and Output devices. Just as one can point to a specific chip, I similarly want to point to a specific panel of boards.
Assembler & Compiler
An assembler is fairly straight forward, while a compiler would better serve to demonstrate the marriage between programming and the hardware to best enable it.
Interfacing
Most all 8-bit computers from this era used a monitor display for output, some supporting graphics in addition to character text. I've chosen instead to use a serial terminal.
The most common video interface was "composite video", making available most any B&W or color TV one already had as the primary display. While this output type is easy to implement, finding display hardware today to use it is another story.
The next logical step up is VGA, which is not as easy to implement, and is itself a standard already in the process of being phased out of common usage.
Serial is bog simple to implement and use, and despite the transformation of RS232 to TTL level signaling and being encapsulated within USB, this is an interface that will not be going away for a very long time.