TMS9928AN

The Texas Instruments TMS9928AN is a Video Display Processor (VDP), a variation of the TMS9918. It distinguishes itself by providing an RGB output signal, a departure from the TMS9918's NTSC composite output. This VDP is designed to work with 16k x 1-bit DRAM, utilizing eight such chips, though it can also accommodate 4k x 1-bit or 8k x 1-bit DRAMs.

A key hardware advantage of the TMS9928AN is its integrated DRAM controller and the independence of its VRAM space from the CPU bus. This architecture simplifies design by eliminating the need for arbitration between display and drawing access. For NTSC output, the chip handles video signal generation, requiring only an external output buffer. For RGB output, color difference signals are generated internally.

This component was used in systems like MSX computers, paving the way for later VDPs such as the V9938 and V9958, which offered backward software compatibility. The TMS9928AN's design facilitated easier hardware implementation for graphics processing in its era.