Ever wondered how Super Nintendo works? There were no "standards" during that dark ages :) Very interesting read about the decisions they were making for chips to render the way they wanted:
https://fabiensanglard.net/snes_ppus_why/
Or how graphics system works:
https://fabiensanglard.net/snes_ppus_how/
There are also many other parts of the system design on same blog, just check the references...