This page was last modified 09:04, 18 November 2021 by Gdx. Based on work by Mars2000you and Tarnyko and others.
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This article is about the MSX standard, as in, the first generation of the MSX standard, unofficially also known as "MSX1".

MSX1 Standard definition

Standard features Obligatory:

  • CPU Zilog Z80A compatible at 3.579 MHz (8-bit)
  • RAM at least 8kB. (Most of machines had 64kB built in.)
  • 32kB Main-ROM containing the BIOS and MSX-BASIC version 1.0)
  • Video Display Processor: Texas Instruments TMS-9918/TMS-9928/TMS-9929
    • Video RAM 16kB
  • General Instrument AY-3-8910 Programmable Sound Generator. 8 octaves and 3 sound channels.
  • At least 70 keys (including five programmable function keys, Graph, Code/Hangul/Kana/РУС, Select, Stop and four arrow keys. Caps and Accents/Dead keys are optional)
  • Connectivity
    • One connector for tape/data recorder. Transfer speed: 1200 or 2400 baud in MSX-BASIC (FSK format). The speed can be altered though, with some POKEing or easily in Machine Language programs.
    • At least one expansion BUS or cartridge slot. Usually it is the cartridge slot. An expansion BUS must have the standard 50 pin. The pins -/+12V and Sound IN may not connected on expansion bus.
    • One or two General Purpose port. The connector is a normal 9-pin D-connector, male. (Game controllers and paddle controllers are optional)

Standard features Optional:

  • Kanji-ROM level 1
  • Floppy disk drive interface
    • 16kB Disk-ROM containing the Disk BASIC and MSX-DOS 1 kernel
    • Floppy disk drive 3.5 or 5.25 inch. Some MSX1 computers were sold together with a disk-drive interface and a 360kB (single sided) floppy drive, mostly 3.5" but also 5.25" (mainly used in Brazil, but in the beginning also in the Netherlands)
  • Printer interface (8-bit, output only, Centronics 14 pin) (optional, but is actually available on most MSX1 computers)
  • MSX-AUDIO with up to 256kB of sample RAM


  • Mice and graphic tablets are not yet standard. BIOS routines don't support them.
  • The game controllers must have one or two buttons (type 1 or Type 2)
  • The drive called Quick Disk with 2.8" disks is not a part of the standard. It's not capable of random access, but it's a kind of tape-stream on a disk (in a spiral). It was also used on other home computers, like the Sharp MZ-700.
  • A 3" (Amstrad) drive was probably also available but never was widely used by MSX users. Since Sony's introduction of the 3.5" floppy drive, micro floppy disks became more or less the standard on MSX machines, especially in Europe and Japan.

Graphic capabilities

These are governed by the used TMS video chips and boil down to the following modes (in MSX-BASIC):

Screen Resolution Colors Description
0 40×24 characters a 6x8 pixels 2 Text mode. 256 chars.
1 32×24 characters a 8x8 pixels 16, a colorbyte per 8 chars. Text mode. 256 chars.

The charset always can be filled with game graphics. A tile mode. MSX-BASIC games typically use this screen as one would be able to 'type' a level onto the screen using PRINT.
2 256×192 pixels
32×24 characters a 8x8 pixels
16, two colors per 8x1 pixels. Bitmap mode.
At the same time a Text mode.

768 chars: the bitmap is made of 3 screen regions, each one a charset a 256 chars. BASIC uses this mode bitmap style with "LINE" style commands, while many games use it as tile mode.
3 64×48 (4×4 pixel blocks) 16 Multi color mode
  • Note that in screen 1 and 2 there is a "color spill" effect
  • 32 sprites available in screen 1, 2 and 3, but only four can be displayed on a row at the same time. Sprites like on game consoles.


MSX1 software was available mostly on cartridge or tapes. Later on some software was also made available on disks (mainly 360kB - 3.5"), but disks for the most part only became popular with the MSX2. Hundreds of games were produced in the 80's for MSX1.

Cassettes were more popular in Europe, while cartridges where more popular in Japan. Cartridge based software had the advantage of instant loading, and less memory needed. But had the disadvantage of higher production cost, especially for larger games. Cassettes had the advantage of low production cost, but were easy to copy with a, common back then, dual tape deck. This is also reflected in the amount of memory the typical MSX came with. As cartridge based software requires less memory, Japanese MSX systems typically had less memory then their European equivalent.

For a short period there was also card software, on a card roughly the size of a credit card. Both Hudson with the BeePack and Electric Software with the SoftCard provided such solutions.

Links to MSX1 software can be found on this page: MSX1 Software.


See the list on the page about the MSX1 Computers.