This is a version of my Raspberry Pi Pico MIDI Splitter that omits the MIDI sockets and instead provides a 5V UART TX style output for use directly with 5V microcontrollers.
Update:
- Find the Build Guide here: Raspberry Pi Pico MIDI Splitter (TTL) – Part 2
Tutorials used in this project:
- Raspberry Pi Pico MIDI Channel Router
- Raspberry Pi Pico Multi MIDI Router – Part 4
- Notes on KiCad for PCB design: Arduino Uno Dual Merge MIDI “Shield” – Part 2
If you are new to microcontrollers, see the Getting Started pages.
The Circuit
I’ve kept the buffered IO for the MIDI OUTs, using 74HCT14 hex inverters once again to level shift between the 3V3 world of the Pico and the required 5V output.
Note there is no current protection on these direct logic links, they are directly connected to the 74HCT14. If driving a microcontroller RX pin, then the current should be limited by the microcontrollers built-in PULL UP resistor, but it is always best to check the datasheets and perform a current calculation to make sure this is ok with the current requirements of the 74HCT14.
UART 0 is still directly connected to a proper MIDI DIN IN and OUT port.
PCB Design
Dispensing with MIDI sockets means I’ve been able to shrink the board down compared to the “full” version.
The UART MIDI IN/OUT breaks out on the right hand side of the board after my standard 3V3 MIDI IN and OUT circuits. All the buffered PIO MIDI OUT ports are over on the left. The Pico itself sits between the two, with USB on the top edge, and can be mounted using header sockets or via a direct SMT soldering.
The TTL serial outputs are just a TX and GND link – so two header pins per port.
Closing Thoughts
If this one works, this will be exactly what I need for my Lo-Fi Orchestra, so I’m looking forward to getting this one back.
Once again, I’ve been able to use some of my discount vouchers with Seeed Fusion to get this board sent off. In fact, this is the first of a new batch that I’ve just sent off.
Kevin
Simple DIY Electronic Music Projects 