Jump to content

Yamaha V9938

From Wikipedia, the free encyclopedia
(Redirected from V9938)
Yamaha V9938 in an MSX2

The Yamaha V9938, also known as MSX-Video or VDP (Video Display Processor),[1] is a video display processor (VDP) used on the MSX2 home computer,[2][3] 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.[4]

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

[edit]
  • Video RAM: 16–192 KB
  • 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)
  • Sprites: 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

[edit]
  • Video RAM: 4 possible configurations
    • 16 KB (modes G4 up to G7 will not be available)
    • 64 KB (modes G6 and G7 will not be available)
    • 128 KB: most common configuration
    • 192 KB, where 64 KB is extended-VRAM (only available as back-buffer for G4 and G5 modes)
  • Clock: 21 MHz
  • Video output frequency: 15 kHz
  • Color encoding: Software switchable between 50 Hz PAL mode and 60 Hz NTSC mode
  • 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

[edit]

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

Basic mode VDP mode MSX system
Screen 0 (width 40) T1 MSX 1
Screen 0 (width 80) T2 MSX 2
Screen 1 G1 MSX 1
Screen 2 G2 MSX 1
Screen 3 MC MSX 1
Screen 4 G3 MSX 2
Screen 5 G4 MSX 2
Screen 6 G5 MSX 2
Screen 7 G6 MSX 2
Screen 8 G7 MSX 2

References

[edit]
  1. ^ Yamaha V9938 MSX-Video Technical Data Book Aug85. ASCII CORP./NIPPON GAKKI. 1985.
  2. ^ Center, MSX Resource (2023-04-02). "Yamaha V9938". MSX Wiki. Retrieved 2025-06-23.
  3. ^ Electronics. McGraw-Hill. 1985.
  4. ^ Packwood, Lewis (2024-01-25). Curious Video Game Machines. White Owl. p. 132. ISBN 978-1-3990-7378-3.

See also

[edit]
[edit]

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

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

Retrieved from "https://en.wikipedia.org/w/index.php?title=Yamaha_V9938&oldid=1299046967"