| ??? 09/19/07 00:35 Read: times |
#144769 - +5V power on the MIDI connector Responding to: ???'s previous message |
Chico Magalhães said:
The +5V on pin 4 on midi in/out/thru connection is there as I said! It's needed to supply the circuit. Your schematic is an optocoupled/drived cable/connection. The upper part of your schematic, (I mean, the midi in,opto isolated) is same as I have on my controller. Note that it's connected through the pull-up resistor to +5V. It's used as the power-supply for the LED in the optoisolator (it goes to the anode); the MIDI signal on pin five toggles and when low, the LED turns on. Note that there is no ground return back to the MIDI out for the voltage on pin 5. If it was there, then there wouldn't be any isolation. And if there's no ground return, you can't use it as a power supply! -a |
