What is it?

HardMPU-WT is an 8-bit ISA expansion card that re-creates the original Roland MPU-401 interface in both of its historical modes: UART and Intelligent. Hand-assembled on a matte-black, gold-plated PCB, it gives any XT/AT/486/Pentium DOS machine a hardware-accurate MIDI port that software recognizes as “MPU-401” at the classic 330 h address. A standard 5-pin DIN OUT/THRU plus jumper-selectable I/O and IRQ let you run it beside or instead of the MPU emulation found on common Sound Blaster cards.

Why did you make it?

Vintage DOS titles such as Princess Maker 1 & 2, Ultima VI, Wing Commander, and a long list of Sierra/LucasArts adventures query the MPU-401’s command register and will remain silent if they see only the dumbed-down UART mode that most 1990s sound cards provide. Modern USB-MIDI adapters do not speak Intelligent mode either, so collectors were forced to hunt rare, expensive Roland “Music Interface” cards or entire LAPC/CM modules. I wanted an affordable, open-hardware solution that could be built today, shipped worldwide, and dropped into any retro PC without cannibalizing an original Roland part.

What makes it special?

Full Intelligent-mode logic: 6801-class microcontroller core coded to answer every MPU-401 status/command handshake that DOS games expect, giving 100 % compatibility with titles that need it. Dual-mode jumper: slide one shunt and the card behaves like a plain UART interface for Windows or trackers that don’t need Intelligent overhead.
Hardware conflict freedom: all I/O (300/330/332/334) and IRQ (2/9/5/7) settings are set with DIP headers, so you can disable the MPU port on your SB16/AWE/ESS and still keep audio playback. ISA-friendly power-up: card powers from 5 V only, generates its own ±12 V for true RS-232-level MIDI current loops, and works in 8-bit slots back to the IBM 5150.
Hand-crafted quality: every board is solder-masked in black, ENIG-finished, visually inspected, programmed, loop-back tested and shipped in an anti-static bag with a printed quick-start sheet and bracket screws. No surface-mount mystery—through-hole parts mean it can be repaired for decades.