Spectravideo SVI-318 Mark II

Collection|Retro Computers

The original Spectravideo computers were released in Australia in January 1993, they actually sold quite well in my home state of Tasmania.

The original Spectravideo design for the computer formed the basis of the MSX standard, but some minor changes to the memory map and the cartridge port makes them incompatible with the MSX standard.

This model is the 2nd version of the base model (thus the Mark II), released in 1984, where the component count was reduced and the RF modulator was moved to part of the main board.


 NameSVI-318 Mark II
 CPUZilog Z80A 3.6Mhz 
 GraphicsTI-9918A
SCREEN 0: Text mode 40x24 characters, two colors (background+foreground). 
Fonts are formed using a 6x8 pixel matrix.  Sprites are not available in this mode.
SCREEN 1: High resolution graphics mode: 256x192, 16 colors. Sprites are available.
Colour resolution is 8x1 pixels: that is, for every group of 8x1 pixels, only one foreground/background color pair may be displayed.
This is a standard TMS-9918A limitation.
Text is also supported in SCREEN1, allowing up to 43x24 characters (with two pixels chopped off the 43rd character). 
SCREEN 2: Low resolution graphics mode: 64x48, 16 colors.  Sprites are available.
The screen is addressed and formed using full 256x192 resolution, with 4x4 block graphics (each 8x8 pixel matrix holds four low resolution pixels).  Sprites are displayed at high resolution (256x192).
Text is also supported in SCREEN2, allowing up to 11x6 characters (with two pixels chopped off the 11th character)
 Memory 16k Main Memory, 16k Video Memory
 Sound AY-3-8910 Three channels, 8 octaves