Are there instructions available for using the device in MIDI Interface Mode? For example, how to wire it to a standard 5-pin or other MIDI connector?
TashRecorder: a Farallon MacRecorder compatible clone
- Thread starter demik
- Start date
-
- Tags
- macrecorder
as @Tashtari said, the device as you know it (that translucent bluebox that I posted that @Mu0n built in his nice video) is unfortunately audio only (Internal Mic or external line in). Long answer below
Citing MIDI in that small box was hard and the BOM was going a little crazy (need other switches, opto couplers and probably Mini DIN to DIN adapters such as this one
As I have no MIDI device myself, I was hoping someone else could respin the PCB (as you may imagine I'm not a fan of shipping stuff that I cannot test). @Mu0n idea is good as well, doing a separate box using the same microcontroller/firmware
However if you would like to experiment we added a header to help people prototype such things. Here are the undocumented header (J3) layout:
- +2.5V (virtual +5V)
- audio (MIDI IN goes there, remove op amp)
- MODE (Connect to pin below to switch to MIDI mode)
- -2.5V (virtual GND)
The ±2.5V power thing of TashRecorder is floating centred to the Mac Ground so the PIC is able to transmit on spec RS422 signals and is also more convenient to work with audio signals
The idea is to build (externally) something like this with an 6N138 optocoupler (schematic from an unrelated project)
Maybe @Tashtari got it further but that's all I had on my notes
Hope it helps
Citing MIDI in that small box was hard and the BOM was going a little crazy (need other switches, opto couplers and probably Mini DIN to DIN adapters such as this one
As I have no MIDI device myself, I was hoping someone else could respin the PCB (as you may imagine I'm not a fan of shipping stuff that I cannot test). @Mu0n idea is good as well, doing a separate box using the same microcontroller/firmware
However if you would like to experiment we added a header to help people prototype such things. Here are the undocumented header (J3) layout:
- +2.5V (virtual +5V)
- audio (MIDI IN goes there, remove op amp)
- MODE (Connect to pin below to switch to MIDI mode)
- -2.5V (virtual GND)
The ±2.5V power thing of TashRecorder is floating centred to the Mac Ground so the PIC is able to transmit on spec RS422 signals and is also more convenient to work with audio signals
The idea is to build (externally) something like this with an 6N138 optocoupler (schematic from an unrelated project)
Maybe @Tashtari got it further but that's all I had on my notes
Hope it helps
I've done that MIDI in subcircuit on breadboard and perfboard a number of times and it worked well with my stock of H11 optocoupler chips from Ali express.
A midi interface typically needs to have a 1MHz oscillation signal divided by exactly 32 to get to the midi spec's 31,250 bps. Is that what the firmware can achieve already?
A midi interface typically needs to have a 1MHz oscillation signal divided by exactly 32 to get to the midi spec's 31,250 bps. Is that what the firmware can achieve already?
Yeah - in MIDI mode (mode select pin pulled low), the firmware generates a 1 MHz clock from the clock output pin and relays the MIDI/audio input pin to the RxD± pins, inverted.