Engineering:Yamaha V9958
From HandWiki
The Yamaha V9958[1][2][3] is a Video Display Processor used in the MSX2+[4] 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[5][6][7] modes with up to 19268 colors and horizontal scrolling registers. The V9958 was not as widely adopted as the V9938.
Specifications
- Video RAM: 128 KB + 64 KB of expanded VRAM
- Text modes: 80 x 24 and 32 x 24
- Resolution: 512 x 212 (4 or 16 colors out of 512) and 256 x 212 (16, 256, 12499 or 19268 colors)
- Sprites: 32, 16 colors, max 8 per horizontal line
- Hardware acceleration for copy, line, fill, etc.
- Interlacing to double vertical resolution
- Horizontal and vertical scroll registers
Feature changes from the V9938
The following features were added to or removed from the Yamaha V9938 specifications:
- Added horizontal scrolling registers
- Added YJK graphics modes (similar to YUV):
- G7 + YJK + YAE: 256 x 212, 12499 colors + 16 color palette
- G7 + YJK: 256 x 212, 19268 colors
- Added the ability to execute hardware accelerated commands in non-bitmap screen modes
- Removed lightpen and mouse functions
- Removed composite video output function
MSX-specific terminology
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 |
| Screen 10 | G7 with YJK and YAE | MSX 2+ and tR |
| Screen 11 | G7 with YJK and YAE | MSX 2+ and tR |
| Screen 12 | G7 with YJK | MSX 2+ and tR |
References
- ↑ (in en) IC Master. United Technical Publications. 2001. https://books.google.com/books?id=8RwSAQAAMAAJ&dq=%22Yamaha+V9958%22+-wikipedia&pg=PA3984.
- ↑ Martín Sesma, Sergio (2016-10-03). Arqueología informática: los ordenadores MSX en los inicios de la microinformática doméstica (Proyecto/Trabajo fin de carrera/grado thesis). Universitat Politècnica de València.
- ↑ Redazione (2008-10-20). "MSX - Vari Costruttori- 1983" (in it-IT). https://www.cyberludus.com/2008/10/msx-vari-costruttori-1983/.
- ↑ Alex, Wulms (1995). "Schermen op MSX - De 2+ schermen". MSX Computer & Club Magazine (72). http://www.msxarchive.nl/pub/msx/mirrors/hanso/hwdoityourself/msxplus.pdf.
- ↑ MSX Licensing Corporation (2022). "The YJK screen modes". http://map.grauw.nl/articles/yjk/.
- ↑ Niemietz, Ricardo Cancho (2014). Issues on YJK colour model implemented in Yamaha V9958 VDP chip. http://rs.gr8bit.ru/Documentation/Issues-on-YJK-colour-model-implemented-in-Yamaha-V9958-VDP-chip.pdf.
- ↑ "VCFe Vortrag vom 2016.04.30 - Homecomputer und Spielkonsolen - Videoarchitekturen als visuelles Medium". http://neil.franklin.ch/Articles/20160430_VCFe_Video_als_Medium.html.
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