Sega SG-1000: Difference between revisions

The system is a simple construction with only a few integrated circuits which contains a Zilog Z80, a TMS9918 VDP, a 76489 PSG, a 74LS139 decoder, a 74LS32 OR gate, 1KB of static RAM accessible to the processor and 16KB of VRAM for the VDP. In the first model, all those components are in their respective packages but some units of the revised SG-1000 ][II integrated most of the logic plus the VDP and PSG in a single integrated circuit which, at the same time, was capable of outputting RGB video, althought this feature was not used (the only output this machine had was RF). The console has no ROM on it, therefore it expects any code to be introduced at the system via the cartridge or the expansion ports.