Daewoo CPC-400S
This page was last modified 16:51, 3 November 2021 by Mars2000you. Based on work by Gdx and Grauw and others.



The Daewoo CPC-400S, also called the X-IIs, is same as CPC-400 but with superimpose and digitize functions. It has been manufactured and distributed by Daewoo on the Korean market.

This model has an extra text mode in Basic, the SCREEN 9. It is a text screen mode based on the graphic SCREEN 6 to display Korean characters.

A switch on the back allows to get stereo PSG sound, with channel A on the left and the two other channels on the right. It's not an ideal stereo output as the sound of the B and C channels can be lower than that of the A channel.

Some strange behavior has also been noticed when using games with a SCC soundchip. Besides, many CPC-400/400S machines were never fully tested before releasing on the market.

Brand Daewoo
Model CPC-400S
Year 1988
Region South Korea
Launch price ₩390,000
RAM 128kB in slot 0-2
VRAM 128kB
Media MSX cartridges, 2DD floppy disk
Video Yamaha V9938
Audio PSG (AY-3-8910A)
Chipset Daewoo DW64MX1
Keyboard layout QWERTY/Korean + numeric keypad
Extras 1 or 2 720kB 3,5" floppy disk drives, reset button, lightpen connector, video digitizer, superimposer, stereo PSG sound, Hangul BASIC
Emulation ROMs dumped and emulated, except for the superimpose, digitize and light pen functionalities. The rear expansion port is treated like a regular MSX cartridge slot.


CPC-400 & CPC-400S with Monitor
Daewoo CPC-400S rear
Daewoo CPC-400S box


The CPC-400S is a MSX2 that does not use a MSX-Engine but a custom IC DW64MX1 that includes the 8255 PPI, slot select circuitry, a memory mapper and various glue logic. The CPU is a Z80A from Goldstar (GSS Z8400A PS).

The main RAM is present on slot 0-2, a configuration that can cause poorly written software to crash. Also, with this layout, the POKE-1,(15-PEEK(-1)\16)*17 trick to workaround buggy software that does not handle subslots properly will cause this machine to freeze.

The mixing with the MSX sound output and the external sound output can be controlled by writing to the I/O port F7h as below.

F7H      W       b0: Back side audio R (“0" for mixing on)
         W       b1: Back side audio L (“0" for mixing on)

Slot Map

Slot 0-0 Slot 0-1 Slot 0-2 Slot 0-3 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh 128kB
Page 8000h~BFFFh Kanji Control
Page 4000h~7FFFh Main-ROM Hangul
Disk ROM
Page 0000h~3FFFh Sub-ROM


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