Yamaha CX5
This page was last modified 15:08, 16 December 2021 by Mars2000you. Based on work by Rderooy and Gdx and others.




The Yamaha CX5, CX5F, CX5M, CX5MII and CX5MII/128 computers were specifically targeted at music and sound production, and as such were regarded by many as non-standard MSX machines. However, they are in fact standard MSX1 computers and can be used as such.

The CX5 is the same MSX1 as the CX5F but with a cheaper keyboard and internal power supply. Two keyboard overlays were provided, one is gray, the other one is black.

Brand Yamaha
Model CX5
Year 1983-11
Region Japan
Launch price ¥59,800
RAM 32kB in slot 0
Media MSX cartridges, side slot modules
Video Texas Instruments TMS9928A
Audio PSG (YM 2149), SFG, MIDI
Chipset Yamaha YM5214
Keyboard layout QWERTY/JP50on
Extras 60 pin module port, FM synthesizer with MIDI IN/OUT connector, music keyboard connector and stereo audio out
Emulation ROM dump needed. See this thread for details


The CX5 was sold with the SFG-01 module plugged into the side slot. There is also an updated version called the SFG-05, sold separately or included with the CX5MII. From BASIC, the music firmware can be launched with CALL MUSIC or _MUSIC.



Yamaha CX5
Yamaha CX5 detail of keyboard
Yamaha CX5 label
Yamaha CX5 underside
Yamaha CX5 manuals
Yamaha CX5 right side
Yamaha CX5 left side
Yamaha CX5 back
Yamaha CX5 box
Yamaha CX5 keyboard overlay
Yamaha CX5 directional key


SFG-01 Screen

More info about the SFG modules on these pages:


The CX5 is a MSX1 with a Z80A from Sharp (LH-0080A) and a side slot, reserved for the SFG-01 or SFG-05 module. The sound modules are 8 note polyphonic 4-op FM synthesizers by Yamaha, based on the YM2151 OPM sound chip (YM2164 in the SFG-05, which is compatible). They can be used in other MSX computers via the UCN-01 side-slot to standard MSX cartridge slot adapter.

The CX5 can be used together with the Yamaha YK-01, YK-10 and YK-20 keyboards for use with the FM synthesizer. The Toshiba HX-MU901 is also compatible.

To use the extension bus as second cartridge slot, you need the Yamaha Single Cartridge Adapter CA-01.

To get 64kB RAM with the CX5, you can insert the URM-01 cartridge in slot 1 or 2 or the SRE-01 module in side slot 3. It means that the 64kB RAM is split between two slots, 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 not work on this machine expanded to 64kB RAM.

Slot Map

Slot 0 Slot 1 Slot 2 Slot 3
Page C000h~FFFFh RAM Cartridge
Page 8000h~BFFFh
Page 4000h~7FFFh Main-ROM
Page 0000h~3FFFh
  • By default the Module slot contains a SFG-01 from 4000-7FFF (which gets mirrored to 0000-3FFF and 8000-FFFF)