albpower2seq4sid Posted March 5, 2012 Report Share Posted March 5, 2012 (edited) Hi, I tried this link, http://www.ucapps.de/mbhp/mbhp_core_lpc17_midi3_extension.pdf But I couln't open it 'cause a I need to connect more devices, I tought to use one more MIDI in/OUT ( #3 ) and two or three IIC modules I have my third SEQ_V4 working but i need more Midi IN/OUTs Sorry, I saw this: http://midibox.org/forums/uploads/tn_gallery_9659_127_3197.png Edited March 5, 2012 by albpower2seq4sid Quote Link to comment Share on other sites More sharing options...
TK. Posted March 5, 2012 Report Share Posted March 5, 2012 http://midibox.org/forums/uploads/tn_gallery_9659_127_3197.png This is the wrong schematic, it fixes a problem with a problematic MIDI device, but it isn't standard! Here the correct link: http://www.ucapps.de/mbhp/mbhp_core_lpc17_midi3_midi4_extension.pdf (I fixed the webpage and added the same link to the MBHP_CORE_LPC17 page now) Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
ilmenator Posted March 5, 2012 Report Share Posted March 5, 2012 There seems to be a small copy/paste error in the PDF: both additional MIDI ports are numbered #3, whereas I think one of those should be #4? Which one? Quote Link to comment Share on other sites More sharing options...
TK. Posted March 5, 2012 Report Share Posted March 5, 2012 Thank you! Fixed Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
albpower2seq4sid Posted March 5, 2012 Author Report Share Posted March 5, 2012 Here the correct link: http://www.ucapps.de/mbhp/mbhp_core_lpc17_midi3_midi4_extension.pdf Ok, I opened that file, only one doubt more: is it 5 Volts or 3.3 Volts in both MIDI OUT'S ( #3 and #4 ) because on the Core LPC17 Schematic on both MIDI OUT, #1 and #2, there are 3.3 Volts ( after the 220 ohms resistors ) I had used both #1 and #2 MIDI OUT ( 3.3 VOlts ) and they are working well Thanks for your reply Best Regards Quote Link to comment Share on other sites More sharing options...
TK. Posted March 5, 2012 Report Share Posted March 5, 2012 Thanks again - the third error: wrong link, wrong enumeration, wrong supply voltage - ok, I created the schematic at new year's eve and was in hurry... ;-) The supply voltage is 3.3V since the output pins of the LPC17 UARTs don't support open drain mode which would allow to pull the voltage to 5V. Note: using 3.3V for the 1k pull-up at the output of the optocoupler shouldn't cause an issue. I changed it this way to avoid one additional cable to a +5V pin. Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
albpower2seq4sid Posted March 6, 2012 Author Report Share Posted March 6, 2012 Thanks again - the third error: wrong link, wrong enumeration, wrong supply voltage - ok, I created the schematic at new year's eve and was in hurry... ;-) The supply voltage is 3.3V since the output pins of the LPC17 UARTs don't support open drain mode which would allow to pull the voltage to 5V. Note: using 3.3V for the 1k pull-up at the output of the optocoupler shouldn't cause an issue. I changed it this way to avoid one additional cable to a +5V pin. Best Regards, Thorsten. Hi Thorsten, I test the MIDI IN/OUT with 3.3 V and they work perfectly. No problem with 3.3 V on optocoupler. MIDI OUT #3 with 3.3V works well. Thanks Thorsten for your support Best Regards, Alberto Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.