uMSX Pro REV.3.90 - 1ChipMSX Clone
What is it?
The latest uMSX Pro Rev.3.90 is here, fully stocked and ready to ship. Our goal is simple: let everyone easily own a 1ChipMSX and get the definitive MSX2+ experience.
Born from the va-de-retro retro computing forum, the uMSX is an MSX2+ FPGA implementation inspired by the Zemmix — one of the first commercially available FPGA-based MSX2+ systems. "uMSX" carries two meanings:
It's a 1ChipMSX clone. To keep PCB manufacturing affordable, the original designer (BCH) split the board into a mainboard and a cartridge slot board, each under 10×10cm. I fully endorse this practical approach.
"Your MSX." 1ChipMSX belongs to everyone. The FPGA and hardware designs are fully open source, so anyone can build their own.
Design Heritage
Original uMSX Rev3.7 PCB by BCH
Gerber reverse engineering by Null
Acrylic case by Xiaohao Studio
Mainboard PCB modifications & optimization by Denjhang, Null
Cartridge slot board modifications by Denjhang, BH2VGM
The VHDL core is the well-known KDL PLD implementation for MSX2+, used by the vast majority of FPGA-based MSX computers. The uMSX uses the first-generation KDL source (also known as ESEMSX).
Hardware Core
Built around the still-accessible Altera EP1C12 FPGA (EP1C12Q240C8N) — millions available from surplus markets at ~$20 each, with hidden 5V tolerance. The board uses compact SMD components (plus a few through-hole) for a clean, modern layout.
4Mbit EPCS4 active-serial configuration flash for firmware
MT48LC16M16A2 SRAM for system memory
NC7WV04P6X clock inverter + 21.47727MHz crystal
953B voltage detector & reset IC
Heavy use of 0603 SMT resistor arrays and 0805 components
Why did you make it?
Soldering a QFP240 EP1C12 is genuinely hard. Fortunately, China has no shortage of skilled soldering foundries, ensuring consistent yield across all my products.
My uMSX Pro line started from the vdr forum's Rev.3.5. I've since iterated through translucent acrylic cases, restored missing features, and now at Rev.3.90 we've reached a mature, integrated design.
What makes it special?
Rev.3.90 Key Upgrades:
Built-in WiFi — ESP8266 module integrated on-board. No dongle needed, 2.4G wireless networking out of the box.
Dual Keyboard Support — Physical switch toggles between PS/2 and USB keyboards. Dedicated on-board USB-to-PS/2 conversion chip ensures full compatibility with virtually all USB keyboards (not just select models).
Complete Classic Video Outputs — VGA + Analog RGB + S-Video + Composite Video. The full 1ChipMSX port combo, covering everything from modern monitors to vintage CRTs.
Reliable Power Switch — Replaced the flaky 2-pin header solution with a proper self-locking switch.
Pre-amp with Volume Control — On-board audio amplifier with physical volume adjustment.
IB0505S Power Filter — Isolated DC-DC module for cleaner audio with reduced noise.
Self-ejecting MicroSD Slot — Push-to-eject mechanism for better handling.
Improved Layout — VGA port repositioned to the rear for cleaner cable management. Enhanced VGA signal quality eliminating color shift and interference.
Two Vertical MSX Cartridge Slots — With dust covers, upright orientation saves desk space.
Integrated Acrylic Case — Mainboard and slot board housed in a single, serious-looking enclosure. No more exposed PCBs or loose ribbon cables.
Core Specifications:
MSX2+ Compatibility — Full architecture reproduction, broad software and game compatibility.
2MB or 4MB Mapped RAM — User-selectable memory options.
V9958 VDP — Sharp graphics, authentic MSX visual experience.
FM + SCC + PSG Audio — FM synthesis, Konami SCC wavetable, and standard PSG for complete MSX sound.
Dual Joystick Ports — Two DB9 ports for multiplayer and classic peripherals.
12V Cartridge Lines — Dedicated power rails for compatible peripherals.
MicroSD Card Support — Up to 4GB usable as hard disk. Pre-loaded with OCM BIOS, system files, and SofaRun game browser.
Verified Compatible Cartridges:
ROM / Multi-mapper: Original game ROMs, multi-mapper carts
Disk interfaces: TDC-600, SD Mapper V1/V2, Beer202 IDE, Multi-controller FDD+IDE, Sunrise IDE
Sound expansion: FMPAC, Wozblaster, SFG-01/05, Philips Music Module, vFM
Multi-function: Carnivore2/2+, MegaFlashROM SCC+ SD + 512K RAM, MSX Pico, Flashjack
Graphics expansion (requires 1.5A PPTC fuse + 5V/2A PSU): TRH9000, Tecnobytes V9990 Powergraph, Sunrise GFX9000
What's in the Box:
Assembled uMSX Pro Rev.3.90 in acrylic case
DC 5V power supply
1GB MicroSD card (pre-loaded with OCM BIOS, system files, SofaRun browser, SCC FlashROM, and floppy emulator)
Optional Add-ons:
MegaDrive controller with Joymega adapter
PS/2 or USB keyboard (if you don't have your own)
Ready Out of the Box
The pre-installed software stack means zero configuration needed. SofaRun lets you browse and launch games without typing commands. Built-in SCC FlashROM and floppy drive emulator handle 2MB ROM games and multi-disk titles seamlessly — disk swapping via keyboard hotkeys.
One uMSX. Zero extra cartridges needed. Play the entire MSX / MSX2 / MSX2+ library.