midi-uart-adapter

PCB layout for a simple MIDI (In-Through-Out) / UART - Adapter according to MIDI 1.0 Specification

Does not directly include footprints for MIDI or TRS plugs but rather provides headers such as to more easily allow customization.

Also allows to use different voltage levels for RX, TX respectively (please use different resistors according to recommendations).

https://github.com/tschiemer/midi-uart-adapter

According to simple table-top tests using a Behringer BCF2000 all three connections (in, through, out) work as expected.

Parts

• LITEON 6N138 or ONSEMI 6N138 Octocoupler
• ONSEMI 1N914 Laser Diode
• Resistors (RA, RB, RC, RD, RE, RF) when Vrx = Vtx = 5V: 220 Ohm 5% 0.25W, Package 1206 (3216 Metric) (ex. Bourns Inc. CR1206-FX-2200ELF )
• Optional Ferrite Beads (FB1-6), 1kOhm @ 1MHz, Package 0603 (1608 Metric) (ex. TDK Corporation MMZ1608Y102BTA00), bridge if not used
• Optional Capacitor (C1), 0.1UF, Package 0201 (0603 Metric) (ex. Murata Electronics GRM033C80J104KE15D), leave unconnected if not used (works, but too tiny package size to solder by hand; well, it's possible ;) )
• Optional Capacitor (C1), 0.1UF, Package 0603 (1608 Metric) (ex. KEMET C0603C104K4RACTU), leave unconnected if not used

The optional parts (ferrite beads and capacitor) are intended to surpress EMI etc.

Connections

H1 (Header 1)

Pin	Description