The earliest home computers (TRS-80 Model I, Apple ][, Commodore PET) used discrete logic for everything other than the microprocessor and RAM. Next generation machines had custom ASICs for the glue logic, display controller and such which brought costs down.
Modern retro-revival computers like the Commander x16 struggle with this because the conventional wisdom is that you need to ship 10,000 units for it to be worth making an ASIC. A display controller, particularly a color display controller, is conceptually simple, a really fun project in discrete logic, but the part count is absurd and since things like the x16 compete with the Raspberry Pi, the cost is a problem. Turns out to be most cost effective to implement a VDP in software with the ESP32
The earliest home computers (TRS-80 Model I, Apple ][, Commodore PET) used discrete logic for everything other than the microprocessor and RAM. Next generation machines had custom ASICs for the glue logic, display controller and such which brought costs down.
Modern retro-revival computers like the Commander x16 struggle with this because the conventional wisdom is that you need to ship 10,000 units for it to be worth making an ASIC. A display controller, particularly a color display controller, is conceptually simple, a really fun project in discrete logic, but the part count is absurd and since things like the x16 compete with the Raspberry Pi, the cost is a problem. Turns out to be most cost effective to implement a VDP in software with the ESP32
https://github.com/AgonPlatform/agon-vdp