I found this interesting UART isolator supporting 3.3v/5v:
Since this module uses an optocoupler in order to achieve the isolation, I wonder if it would be suitable for direct use with a MIDI port without additional resistors or diode.
Maybe! It depends on the opto isolators and if they are fast enough. Your link does not work.
It's plenty fast, claiming a baud rate of up to 250,000, which is more than enough considering MIDI operates at 31,250.
I know you only need an isolator for input, but I was curious if the linked UART isolator would be able to process the signal coming from the MIDI port because it's usually meant to operate the LED of an optocoupler.
(One thing for example that throws me off is that the UART isolator appears to require VCC and GND on both sides. I guess a MIDI port would have to carry GND, but does it also carry a VCC or is it not necessary?)
MIDI connection is one closed circuit, from VCC to 4pin midi out - 4 pin midi in - optocoupler - pin5 midi in - pin5 midi out - RX pin arduino. so, when RX set to LOW, on other side light opto up and generate LOW on own pin 6.
and GND is only on OUT side, connected to the cable shielding, on IN side not.
So I'm only getting VCC (pin 4) and TX (pin 5). How would I connect it to the UART isolator then? It would seem I'm missing GND.
Anyone?
midi have an optoisolator. no need of an UART isolator.
The MIDI spec requires the use of an optoisolator for receiving MIDI signals. So if you want to solder a MIDI port for receiving MIDI signals to your microcontroller, you must add an optocoupler by yourself. This is not done by the device sending the signal.
Since the UART isolator uses an optocoupler, I'm wondering if I could just use that instead of soldering my own optocoupler circuit.
It seems to me, you cannot use a UART isolator to receive MIDI signals because MIDI uses a current-based signaling method, which seems fundamentally different from the voltage-based signaling of UART. But I don't know maybe it's just a question of correctly wiring the MIDI port to the UART isolator.
ok. connect two UART isolators one after one. i think you understand then the issue quicker.
I don't understsnd how this would help.
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