One Chip MSX
This page was last modified 09:24, 19 February 2018 by Mars2000you. Based on work by Gdx and Rderooy and others.
One chip MSX



One chip MSX package

The One chip MSX, or 1chipMSX as the D4 Enterprise distributional name for the ESE MSX System 3, is a re-implementation of an MSX-2 computer that uses a single FPGA to implement all the electronics (except the RAM) of an MSX-2, including the MSX-MUSIC and SCC+ audio extensions.

The system is housed in a transparent blue plastic box, and can be used with a standard monitor (or TV) and a PC keyboard. Original MSX cartridges can be inserted, and SD and MMC memory cards can be used as an external storage medium. Even though it lacks a floppy disk drive, disks are supported through emulation on a memory card. MSX-DOS is also supported. Due to its VHDL programmable hardware, it's possible to give the device new hardware extensions by running a reconfiguration program in MSX-DOS. The "one chip-MSX" is equipped with two USB connectors that can be used after adding some supporting VHDL code.

The One Chip MSX also came with a short English instruction manual, including a short introduction to VHDL and the full VHDL code used to achieve MSX2 compatibility.

The ESE MSX System 3 was designed by ESE Artists' Factory and distributed as 1chipMSX by D4 Enterprise and was supposed to be distributed outside Japan by Bazix. However, due to RoHS regulations in Europe it could not be distributed to Europe in its original form, and the European market had to wait for an adapted version which would be produced through Bazix and distributed to Europe by Bazix.

Bazix stopped being the representative of MSX Association and dissolved, and thus did not bring the 1chipMSX to the Western market. In the end, MSX Association was dissolved resulting in a shift of all intellectual property rights concerning MSX to MSX Licensing Corporation.

Several MSX fans have modified the original VHDL code to improve the original features and add new features including MSX2+ compatibility, upgrade of the memory mapper to 4MB, addition of the BASIC KUN compiler.

Brand ESE
Type One chip MSX
Year 2006
RAM 1MB in slot 3-0 (upgraded to 4MB)
VRAM 128kB
Media SD/MMC card, MSX Cartridges
Video Emulated V9938 / V9958 by the FPGA
Audio Emulated PSG, MSX-MUSIC and SCC by the FPGA
Chipset Altera Cyclone EP1C12Q240C8N FPGA chip
Extras FPGA, 2x USB, VGA connector, PS/2 connector


  • Altera Cyclone EP1C12Q240C8N FPGA chip
  • 32 MB SDRAM

Default configuration

By default, the One Chip MSX is configured as follows:

  • MSX 2 computer system
  • 1 MB RAM
  • 128kB VRAM
  • Kanji-ROM
  • MSX-DOS2 with FAT16 support
  • MEGA-SCSI compatible support for SD card as primary drive

Slot Map

Slot Slot
0-0 0‑1 0-2 0-3 Slot 1 Slot 2 3-0 3-1 3-2 3-3*
Bank C000h~FFFFh Cartridge
Slot 1
Slot 2
Bank 8000h~BFFFh
Bank 4000h~7FFFh Main-ROM Kanji
Disk ROM
Bank 0000h~3FFFh MSX-Music Sub-ROM

(*) Slot 3-3 contains the IPL rom whose function is to launch the hardware-emulated MSX2 or MSX2+ computer

  • The BASIC Kun rom is not present on the original configuration
  • The Disk ROM is combined with MSX-DOS 2.31 (special version for Mega-SD), it's a 64kB ROM with a specific mapper.


  • SD/MMC card slot
  • 2 MSX Cartridge slots
  • 2 audio outputs
  • S-Video video output
  • Composite video output
  • VGA video output
  • PS/2 keyboard connector
  • 2 USB connector
  • 2 MSX Joystick ports
  • FPGA I/O pin (40 pins and 10 pins)

Dip Switches

Dip Switches with Original PLD

The meaning of the dipswitches on the bottom side:

No.1+2 : Video output mode 00 : composite video 01 : RGB/SCART (15KHz) 10 : VGA (31KHz) 11 : VGA (31KHz) full brightness

No.3 : RCA-red connector function 0 : CMT mode (the RCA works as EAR/MIC connector) More info 1 : Sound output (same as RCA-white plug)

No.4 : Keyboard assignment 0 : (Japanese) 106/109 1 : (International) 101/104

No.5 : MegaSD enable 0 : disable 1 : enable

No.6 : CPU speed 0 : 3.58MHz 1 : 10.74MHz

No.7+8 : logical slot2 operation mode 00 : real cartridge slot2 01 : ESE-SCC disk / Snatcher-SD snatcher 10 : ESE-RAM_ASC8K 11 : ESE-RAM_ASC16K

Dip Switches when flashed with KdL PLD



We should probably make the CD that came with it for download here also, but for now it is at:

Firmware updated by KdL can be found here: