The PI-MIDI is a MIDI HAT for the Raspberry Pi. It attaches to the Pi’s GPIO pins and gives it a proper MIDI input, stereo RCA output, an audio input for mixing, and a dedicated port for connecting to MiSTer FPGA. Paired with the mt32-pi software synth, it becomes a small, cheap, authentic-sounding stand-in for a Roland MT-32 or Sound Canvas.
What it is
On the connectivity side the board provides:
- a MIDI DIN input for connecting MIDI devices (including a DOS PC via a gameport MIDI cable)
- stereo RCA output, a big step up in quality from the Pi’s own audio jack
- a 2.5 mm audio input, so Sound Blaster effects from the PC can be mixed with the synthesised MIDI into one output
- a user port that looks like USB but is a direct IO connection for MiSTer FPGA
It also has a rotary dial, jog wheel, two buttons and a 1.3” OLED screen for changing volume, synth mode and options without a keyboard.
mt32-pi
mt32-pi is a bare-metal kernel that turns a Raspberry Pi 3 or later into a Roland MT-32 emulator (via Munt) and a SoundFont synthesizer (via FluidSynth). It natively supports GPIO MIDI interfaces like the PI-MIDI, so the two together make a DIY MIDI appliance with the sound and feel of a classic synth. MT-32 mode covers early-90s games; SoundFont mode covers later General MIDI and Sound Canvas titles.
Why I rate it
If you cannot get hold of a real MT-32 or Sound Canvas, a Pi plus PI-MIDI is the option I would recommend. It is plug and play, simple to operate from the front-panel controls, and to my ear produces very authentic sound. The MIDI-DIN input also lifts the DOS-extender limitation of the cheaper serial-MIDI approach (where games like Doom will not work).
The MiSTer connection
The mt32-pi and MiSTer projects collaborated on a direct cabling solution: a single USB A-to-A cable between the PI-MIDI’s user port and the MiSTer IO board user port carries MIDI data and powers the Pi. The PC, Atari ST, Amiga and X68000 cores can all use it.