The Yamaha V9938 is a
video display processor (VDP) used on the
MSX2 home computer
Home computers were a class of microcomputers that entered the market in 1977 and became common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a s ...
, 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.
The Yamaha V9938, also known as MSX-Video or VDP (Video Display Processor), 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
The Yamaha V9958 is a Video Display Processor used in the MSX2+ and MSX turbo R series of home computers, as the successor to the Yamaha V9938 used in the MSX2. The main new features are three graphical YJK modes with up to 19268 colors and hori ...
.
Specifications
*
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
*
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
A clock or chronometer is a device that measures and displays time. The clock is one of the oldest Invention, human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, a ...
: 21 MHz
* Video output frequency: 15 kHz
* Color encoding: Software switchable between 50 Hz
PAL mode and 60 Hz
NTSC
NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170.
In 1953, a second ...
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
A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus'' ...
*
Resolution:
** Horizontal: 256 or 512
** Vertical: 192p, 212p, 384i or 424i
* Color modes:
**
Paletted RGB: 16 colors out of 512 (
9-bit RGB)
** Fixed RGB: 256 colors
* 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:
{, class="wikitable" border="1" width=50%
!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
See also
*
Texas Instruments TMS9918
*
Yamaha V9958
The Yamaha V9958 is a Video Display Processor used in the MSX2+ and MSX turbo R series of home computers, as the successor to the Yamaha V9938 used in the MSX2. The main new features are three graphical YJK modes with up to 19268 colors and hori ...
External links
MSX-Video Technical Data Book, for Yamaha V9938 (August 1985
bitsavers.org
V9938 programmer guide
http://rs.gr8bit.ru/Documentation/V9938-programmers-guide.pdf
Graphics chips
MSX hardware