Daewoo DW64MX1
This page was last modified 16:49, 19 August 2016 by Mars2000you. Based on work by Gdx and RetroTechie and others.

The DW64MX1 is an MSX2 engine IC designed by Daewoo. It includes the following features:

  • Intel 8255 compatible Programmable Peripheral Interface (PPI)
  • Slot select circuitry
  • DRAM control signals
  • 256 KiB memory mapper
  • Chip selects for VDP, PSG, Real Time Clock (RTC) and printer. Note that it does not include a PSG or RTC, only chip select signals for those IC's
  • Keyboard control, Caps Lock LED
  • Cassette interface

It's used in a few MSX1 computers based on the Daewoo CPC-200, all MSX1 Daewoo consoles, all MSX2 Daewoo consoles and computers, including the machines released under another brandname.

Machines using this IC normally have their RAM in slot 0-2. Much software has a problem with that, even though it's perfectly fine according to MSX standard. For example the infamous POKE -1,... workaround doesn't work & causes such machines to hang.

This IC is packaged in a 64 pin "Shrink" DIP (same as V9938).


DW64MX1 chip
(photo by usario_msx2)


Pin I/O Signal function
1 O MPX DRAM address multiplexer select
2 O CAS02 DRAM Column Address Strobe slot 0-2
3 O MA14
Memory mapper
expanded address lines
(64/128/256 KB)
4 O MA15
5 O MA16
6 O MA17
7 O RA7 DRAM address / refresh bit 7
8 I A0

Z80 Address Bus
9 I A1
10 I A2
11 I A3
12 I A4
13 I A5
14 I A6
15 I A7
16 O GND Ground
17 I A14 Z80 Address Bus
18 O ROMCS Main ROM Chip Select
19 O SLT01
Slot select outputs
20 O SLT2
21 O SLT03
22 O PSG_CLK PSG clock (1.79 MHz)
23 I RESET Hard Reset
24 O YA (lsb)

Keyboard scan row select
25 O YB
26 O YC
27 O YD (msb)
28 O Y10 Keyboard row scan signal
29 O PPISND PPI Sound Output (Keys)
30 O CAPS Keyboard Caps Lock LED Signal
31 O RD_KEYS Keyboard Read Strobe
32 I VCC +5V power supply
33 O SLT3 Slot 3 Select Output
34 O SLT1 Slot 1 Select Output
35 O BUSDIR Data Bus Buffer Control

Z80 control signals
39 I RD
40 I WR
41 I M1
44 I A15 Z80 Address Bus
45 O PSG_CS PSG Chip Select
46 O VDP_CS VDP Chip Select
47 O REM Cassette Tape Motor On/Off
48 O GND Ground
49 O CMO Cassette tape write signal
50 I/O D0

Z80 data bus
51 I/O D1
52 I/O D2
53 I/O D3
54 I/O D4
55 I/O D5
56 I/O D6
57 I/O D7
58 O PWR Printer Write data latch
59 O PSTB Printer Strobe output
60 I BUSY Printer BUSY input
61 O RTC_CS RTC Chip Select
62 O RTC_AL RTC Address Latch
63 I CPU_CLK CPU clock (3.58 MHz)
64 I VCC +5V power supply

Source: [1]