Yamaha V9958

Yamaha V9958

Yamaha V9958(ceramic package)

The Yamaha V9958 is a Video Display Processor (VDP) used in MSX 80s home computers. More specifically, the MSX2+, MSX turbo R and the "TIM" upgrade to the TI-99/4A.

The Yamaha V9958, also known as MSX-Video, is the successor of the Yamaha V9938. It was clearly conceived not to be a very major upgrade to its predecessor, which hampered its adoption. The main new features are three graphical YJK modes (with up to 19268 colours) and horizontal scrolling registers.

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 colours out of 512) and 256 x 212 (16, 256, 12499 or 19268 colours)
• Sprites: 32, 16 colours, max 8 per horizontal line
• Hardware acceleration for copy, line, fill, etc.
• Interlacing to double vertical resolution
• Horizontal and vertical scroll registers

Detailed specifications

For detailed specifications, please refer to the Yamaha V9938 page, with the following additions:

• Horizontal scrolling registers
• YJK graphics modes (similar to YUV)
  • G7 + YJK + YAE: 256 x 212, 12499 colours + 16 colour palette
  • G7 + YJK: 256 x 212, 19268 colours
• Ability to execute hardware accelerated commands in non-bitmap screen modes
• Lightpen and mouse functions from V9938 were removed

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