As you correctly pointed out, 32150 isn’t even possible. I’m pretty sure this is actually *two* mistakes, despite his blog saying “baud rate, 32150 is not a mistake”. Posted in Musical Hacks Tagged atmega32u4, AVR, lufa, midi, Midi adapter, pro micro, usb midi Post navigation

We’ve featured several of ’s hacks here over the years, the most recent being the Beaglebone Pin-Toggling Torture Test and from earlier, How to Turn A PC On With a Knock And An ATTiny. Besides this, his code is limited in functionality to only handle a few messages, mainly for playing a piano, and does not have full-fledged MIDI capabilities. He found that a slightly higher baud rate fixes a problem in the AVR USART implementation which tends to miss consecutive bytes due to the START edge not being detected. The interesting part is his use of a 32.15 kbps baud rate even though the MIDI specification requires 31.25 kbps. He wrote his own code to handle MIDI (UART) to USB MIDI messages conversion. The heavy lifting is all done in the firmware, for which used LUFA - the Lightweight USB Framework for AVR’s. After testing his simple circuit on a bread board, he managed to squeeze it all inside an old USB dongle housing, stuffing it in dead-bug style. He reckons it cost him about $5 to build each of his cheap USB MIDI adapters which receive notes and pedal data from the keyboard’s MIDI OUT and transmit them to a computerīesides the Pro Micro clone, the only other parts he used are a generic opto-coupler, a couple of resistors and a MIDI connector. Based on the ATmega32U4, these clones were just right for his application, and the cheapest to boot. This lack of USB support was a deal killer for him, so after hunting some more he settled on a clone of the Sparkfun Pro Micro. With some tinkering, he was able to build one using an Adafruit Pro Trinket which has onboard hardware UART (but no USB). But he needed several converters, and using the Teensy LC was going to cost him a lot more than he was willing to spend. He used a Teensy LC to build one for himself and it did the job quite well. Became frustrated with cheap but crappy MIDI to USB converters, and the better commercial ones were beyond his budget.

Midi to usb cable