Yamaha V9938

Image:V9938c 03.jpg|thumb|right|300px|Yamaha V9938 in an MSX2
The Yamaha V9938, also known as MSX-Video or VDP ',' is a video display processor used on the MSX2 home computer, as well as on the Geneve 9640 enhanced TI-99/4A clone, and the Tatung Einstein 256. It was also used in a few MSX1 computers, in a configuration with 16kB VRAM. It was also used in the Zemmix V console.
The Yamaha V9938 is the successor of the Texas Instruments TMS9918 used in the MSX1 and other systems. The V9938 was in turn succeeded by the Yamaha V9958.

Specifications

Video RAM: 4 possible configurations
* 16 KB
* 64 KB
* 128 KB: most common configuration
* 192 KB, where 64 KB is extended-VRAM
Clock: 21 MHz
Video output frequency: 15 kHz
Color encoding: Software switchable between 50 Hz and 60 Hz modes
Sprites: 32, 16 colors, max 8 per horizontal line
Hardware acceleration, with copy, line, fill etc. With or without logical operations.
Vertical scroll register
Capable of superimposition and digitization
Support for connecting a lightpen and a mouse
Resolution:
* Horizontal: 256 or 512
* Vertical: 192p, 212p, 384i or 424i
Color modes:
* Paletted RGB: 16 colors out of 512
* Fixed RGB: 256 colors
Screen modes
* Text modes:
** T1: 40 × 24 with 2 colors
** T2: 80 × 24 with 4 colors
** All text modes can have 26.5 rows as well.
* Pattern modes
** G1: 256 × 192 with 16 paletted colors and 1 table of 8×8 patterns
** G2: 256 × 192 with 16 paletted colors and 3 tables of 8×8 patterns
** G3: 256 × 192 with 16 paletted colors and 3 tables of 8×8 patterns
** MC: 64 × 48 with 16 paletted colors and 8×2 patterns
** All modes with 192 lines can have 212 lines as well
* Bitmap modes:
** G4: 256 × 212 with 16 paletted colors
** G5: 512 × 212 with 4 paletted colors
** G6: 512 × 212 with 16 paletted colors
** G7: 256 × 212 with 256 fixed-colors
** All modes with 212 lines can have 192 lines as well
** All vertical resolutions can be doubled by interlacing

On MSX, the screen modes are often referred to by their assigned number in MSX-Basic. This mapping is as follows: