Computers Overview
Commodore PET
Sinclair ZX80
Sinclair ZX81
BBC Micro
Commodore 64
Sinclair Spectrum
Memotech MTX
    About
    Library
    Manuals
    Options
    Photos
    Projects
      CFX
      Hardware Hacks
      Legacy (1980s)
      MAGROM
      MTXPlus+
          Architecture
              CPU
              Diagnostics
              Games ROM
              I/O Ports
              Power
              System Bus
              Video
                  Specs
                  Design
                  Build
                  PCB
          Design Data
          Firmware
          Parts
          Software
      PAL Reader
      Programmers
      ReMemotech
      ReMemorizer
      SDX
    Repairs
    Software
    Tools
    User Groups
    Video Wall
Memotech CP/M
Atari ST
DEC 3000 AXP
OpenVMS
Raspberry Pi

 

 
 
 

"MTX Plus+" Video Board

Video Specifications

MTXPlus+ uses a Yamaha V9958 VDP, designed for MSX 2+, it is backward compatible with the Texas Instruments TMS9918 used in the original MTX computer.

Using an MTX compatible ROM, MTXPlus+ will be limited to the video features provided in the original MTX.

 

VDP Feature Comparison
Computer MTX/MSX MSX2 MSX2+ & MTXPlus+
VDP TMS9918 V9938 V9958
Video RAM (min/max) 16KB 128KB (64/192) 128KB (128/192)
Resolution : text 24 x 40 24 x 40 24 x 40
24 x 32 24 x 32 24 x 32
  24 x 80 24 x 80
Resolution : pixels h x v 256 x 192 512 212 256 212 512 212 256 212
Colours 16 16 from 512 256 16 from 512 256
        256212 YJK 256212 YJK/RGB
         19268 12499
Sprites Number 32 32 32
Colours 1 16 16
Max per line 4 8 8

 

Wikipedia has a useful page that compares the video quality and palettes of a number of different 8-bit computers, including the MSX range using the TMS9918, V9938 and V9958. The images below were copied from there, clicking on the links will open the relevant entry on the Wikipedia page
Original MTX/MSX MSX2 MSX2+

8 Bit RGB

Mode 2

Mode 8 Mode 10/11
Horizontal 256 256 256
Vertical 192 212 212
Colours 16 256 12499

Audio

The MTXPlus+ Video board also contains the sound interface, comprising the same chip used in the original MTX, a Texas Instruments SN76489 Programmable Sound Generator.

 

 

 

References:

Roger Samdal's Spectravideo site, VDP page

GR8BIT project, Eugeny Brychkov, GR8BIT Knowledge Base article on adding Composite and S-Video output (KB0014).

 

mailto: Webmaster

 Terms & Conditions