I decided to build the computer in Digital, a simulator for digital logic that is based on Logisim but much improved. Just the name is a bit too common when googling

In order to make a simple TTA computer, a few things are needed.

A CPU capable of moving data
A program counter
An ALU
A branch block

I want the CPU to be a von Neumann type of CPU, meaning that there is one memory bus with code to execute and RAM. To have a useable amount of memory, a 16 bit address, in order to address 64KB of RAM, is probably nice. Let’s just make it a 16 bit CPU when we are busy.