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Wikipedia / Yamaha V9938

The Yamaha V9938, also known as MSX-Video or VDP (Video Display Processor), is a video display processor (VDP) 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 Super 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: 16–192KB

  • Text modes: 80 × 24, 40 × 24 and 32 × 24

  • Resolution: 512 × 212 (16 colors from 512), 256 × 212 (16 colors from 512) and 256 × 212 (256 colors)

  • Spritess: 32, 16 colors, max 8 per horizontal line

  • Hardware acceleration for copy, line, fill and logical operations available

  • Interlacing to double vertical resolution

  • Vertical scroll register

Detailed specifications

Video RAM: 4 possible configurations

  • 16KB (modes G4 up to G7 will not be available)

  • 64KB (modes G6 and G7 will not be available)

  • 128KB: most common configuration

  • 192KB, where 64KB is extended-VRAM (only available as back-buffer for G4 and G5 modes)

  • Clock: 21MHz

  • Video output frequency: 15kHz

  • Color encoding: Software switchable between 50Hz and 60Hz modes

  • Sprites: 32, 16 colors (1 per line. 3, 7 or 15 colors/line by using the CC attribute), 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:

Screen modes

Text modes:

  • T1: 40 × 24 with 2 colors (out of 512)

  • T2: 80 × 24 with 4 colors (out of 512)

  • 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 (similarly 48 → 53 in MC)

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 (similarly 48 → 53 in MC)

  • All vertical resolutions can be doubled by interlacing

MSX-specific terminology

On MSX, the screen modes are often referred to by their assigned number in MSX-Basic. This mapping is as follows:Note: Screen 9 was reserved for South Korean MSX2 units.

References

See also

MSX-Video Technical Data Book, for Yamaha V9938 (August 1985) bitsavers.org

V9938 programmer guide http://rs.gr8bit.ru/Documentation/V9938-programmers-guide.pdf