The Radio Shack TRS-80 was a much-loved machine across America. However, one thing it lacked was MIDI. That’s not so strange given the era it was released in, of course. Nevertheless, [Michael Wessel] has seen fit to correct this by creating the MIDI/80—a soundcard and MIDI interface for this old-school beast.
The core of the build is a BluePill STM32F103C8T6 microcontroller, running at a mighty 75 MHz. Plugged into the TRS-80s expansion port, the microcontroller is responsible for talking to the computer and translating incoming and outgoing MIDI signals as needed. Naturally, you can equip it with full-size classic DIN sockets for MIDI IN and MIDI OUT using an Adafruit breakout module. None of that MIDI Thru nonsense, though, that just makes people uncomfortable. The card is fully capable of reproducing General MIDI sounds, too, either via plugging in a Waveblaster sound module to the relevant header, or by hooking up a Roland Sound Canvas or similar to the MIDI/80s MIDI Out socket. Software-wise, there’s already a whole MIDI ecosystem developing around this new hardware. There’s a TRS-80 drum tracker and a synthesizer program, all with demo songs included. Compatibility wise, The MIDI/80 works with the TRS-80 Model I, III, and 4.
Does this mean the TRS-80 will become a new darling of the tracker and chiptune communities? We can only hope so! Meanwhile, if you want more background on this famous machine, we’ve looked into that, too. Video after the break.
This is wonderful! MIDI has a straightforwardness that appeals to me. Of course I know nothing about it after the ’80s. Built a studio based around a PC-XT clone. Cakewalk4Life!
It’s been ages since I’ve seen anyone mention Cakewalk, it was definitely my first productive real aren’t at midi and I still remember it fondly. These days I am usually using midi and dmx for other things, it turns out it’s great for everything from stage lighting to robotics.
There is something wonderfully Goldbergian — and hack, in the best sense of the word — about using a a device that is orders of magnitude more powerful than the TRS-80 as a peripheral for same.
Back then it wasn’t terribly uncommon for a peripheral to outclass the main machine. That’s especially the case for audio peripherals, but even the cost of a scsi interface card was due to having hardware offload for all of it’s functions and the multiplexing of the drives it could support.
You could even say the true Goldbergian design was later reversing this to run most operations on the host, but bounce back and forth for hardware access and interrupts, then layer APIs, libraries and applications on top of that.
Disk storage (Commodore 1541)
Printing
MIDI/audio gear
Communications (modems, terminals)
Add-on processors (Z80 cards)
Quite a few back in the day.
Oddly, yes, my first thought was the disk drives for my Commodores. Sooo many 65xx processors in such an ecosystem (and, if C128 and like, toss in the (Z80 =))
I do think it would be cool to design a “mostly” period peripheral that has all of the necessary bandwidth to operate in realtime with the host clock. I would settle for doing it on an FPGA though.
Pretty much especially when the first Atari with MIDI was 1985 (520ST). About the same time as the TRS-80 Color Computer (1000). External though was Sequential Circuits Model 64 cartridge for the Commodore 64, Passport Designs MIDI for the Apple II, and Atari 800 had theirs.
This is the core of the music I make, if you want to see me check it out online, @downpoly on YouTube.
Thanks for the post, guys… also check out Downpoly who is doing some great music with MIDI-80 – highly recommended!
https://youtu.be/f0iKvuZr98E
https://youtu.be/Pxf6AB6l7uU
Also here…
https://2roommusic.com/downpoly
Hey, Michael, wonderful hack! :-)
TRS-80 people just can’t resist adding -80 to the end of whatever project they’re working on
The STM32 ‘Blue Pill’ could emulate the TRS-80, do it much faster, and still have gobs of processing power left for the MIDI.
But as a pioneer of the TRS-80 Model I, II, III, IV, Coco, Coco II, Model 100, and many others, I say BRAVO!
By the time MIDI came out the TRS 80 was in decline. The Coco lasted a bit longer and had a cartridge port that would’ve been a great place to put one of these.
Cool project, though!
This story resonates with me. Back in the early 90s, I decided I was gonna add MIDI Out to my TRS-80 Model III. I built a PCB that fit into the UART socket. I decided I would never use 50 Baud mode, so I made a circuit that swapped in a high speed oscillator when 50 Baud was selected, over-clocking the UART to 31250 Baud. Then I used a single transistor on the TX line to get close enough MIDI spec. I used it to drive a Casio keyboard and it worked!