Keith Posted June 21, 2012 Report Share Posted June 21, 2012 I'm using the GM5 to simply input some monophonic, MIDI data (no 'MIDI out') from a microprocessor. Is it really necessary to opto-isolate this stream into the chip? I'm using the MidiBox schematic as a reference. Also, the jumpers shown on the midi-box schematic have me a little baffled for my purpose. '1,0,0' (1 I/Os)? Or '1,1,0' ('I only') for J1,2,3. J6 I can't see a reference for. J8 not sure about. Thanks for any help.-Keith Quote Link to comment Share on other sites More sharing options...
Keith Posted June 22, 2012 Author Report Share Posted June 22, 2012 Okay, figured out J6. Still unsure about J1,2,3 configuration for my purpose. And not still not sure what the distinction is between midibox.org configuration and polytec.com configuration (jumper 8) To opto-isolate or not. I'm using the GM5 to simply input some monophonic, MIDI data (no 'MIDI out') from a microprocessor. Is it really necessary to opto-isolate this stream into the chip? I'm using the MidiBox schematic as a reference. Also, the jumpers shown on the midi-box schematic have me a little baffled for my purpose. '1,0,0' (1 I/Os)? Or '1,1,0' ('I only') for J1,2,3. J6 I can't see a reference for. J8 not sure about. Thanks for any help.-Keith Quote Link to comment Share on other sites More sharing options...
nILS Posted June 22, 2012 Report Share Posted June 22, 2012 1) Opto: Yes, always. 2) config: Mainly the name under which the device shows up on your PC 3) Jumpers: You probably want 110 (one input), won't hurt to have the option of adding an output. Quote Link to comment Share on other sites More sharing options...
Keith Posted June 22, 2012 Author Report Share Posted June 22, 2012 Thanks niLS. So even though the micro that is spitting out the MIDI dat is on the same board as the GM5, I still need to opto-isolte, yes? I thought the ground loop type problem was just because of a MIDI cable. My device will be using the legacy MIDI on a Mac. So once I plug it in, I suppose I can just fiddle with the J8 jumper and see which setting responds. Before your response, I was going to go with '110' and let the output 'hang'. So you coming up with the same idea just confirms that. Thanks again, Keith Quote Link to comment Share on other sites More sharing options...
Keith Posted June 23, 2012 Author Report Share Posted June 23, 2012 One more question: since I'm not using a lot of the I/O (just one input) and not using the eeprom, do I need to ground the I/Os not used or are there pull-ups enabled on them? Thanks,Keith Quote Link to comment Share on other sites More sharing options...
nILS Posted June 24, 2012 Report Share Posted June 24, 2012 If you jumper them accordingly the pins will be disabled on the gm5. So you can just let them float (also, as a general rule, you do not want to ground output pins, only inputs). Quote Link to comment Share on other sites More sharing options...
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