Yamaha V9938 in an MSX2 The Yamaha V9938 , also known as MSX-Video or VDP (Video Display Processor), [ 1] video display processor (VDP) used on the MSX2 home computer ,[ 2] [ 3] Geneve 9640 enhanced TI-99/4A clone,[ 4] Tatung Einstein 256 .[ 5] [ 6] MSX1 computers, in a configuration with 16kB VRAM. It was also used in the Zemmix V console.[ 7]
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 .
Video RAM : 16–192 KBText 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 lineHardware acceleration for copy, line, fill and logical operations availableInterlacing to double vertical resolutionVertical 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 MHzVideo output frequency: 15 kHz
Color encoding: Software switchable between 50 Hz and 60 Hz modes
Sprites : 32, 16 colors (1 per line. 3, 7 or 15 colors/line by using the CC attribute), max 8 per horizontal lineHardware 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
MSX-Video Technical Data Book, for Yamaha V9938 (August 1985) bitsavers.org
V9938 programmer guide
http://rs.gr8bit.ru/Documentation/V9938-programmers-guide.pdf
