monokinetic Posted September 13, 2008 Report Share Posted September 13, 2008 Hi all,to get an extra Midi in on my MB Sequencer I installed the remaining parts for my IIC module. FYI the 4 banksticks and the IIC Midi out work absolutely fine. I seemed to have most things working, except that after receiving 10 or 12 events the TX light on the IIC board stops flashing :(To do some testing I loaded up the loopback IIC test application and noticed in the readme:Note:the yellow LED will only flicker until the MIDI buffer of the MBHP_IIC_MIDI slave is full. This scenario can happen if the core cannot poll for the incoming data. This means in other words: this effect can be noticed, if the SC/SD lines are not connected correctly.I have traced the SD and SC lines from the core through the IIC module and to my 4X bankstick module and most things seems to be ok. The only things that seems a bit strange is that if I measure the resistance between SD and SC I get 2K. Is that right?TIA for any help!Dave mK Quote Link to comment Share on other sites More sharing options...
stryd_one Posted September 13, 2008 Report Share Posted September 13, 2008 Seeing as they're separate lines the resistance should be infinite so you have a short. Quote Link to comment Share on other sites More sharing options...
monokinetic Posted September 14, 2008 Author Report Share Posted September 14, 2008 Hiya,I removed all of the IIC stuff from the bus, still the same 2K resistance between SD and SC. I then traced my Core V3 carefully and I cant see any bridges even with a magnifying glass :(@Stryd are you 100 percent sure there should be no resistance? I ask because on the Core schematic SD and SC both go through 1K resistors to the 5V line. So my original logic was that in fact there would be 2K resistance between the SD and SC. Or am I missing something?D Quote Link to comment Share on other sites More sharing options...
nILS Posted September 14, 2008 Report Share Posted September 14, 2008 I am pretty sure stryd was referring to the IIC board without anything connected to it. In that case the resistance should be infinite (not "no resistance").When connected to the Core ~2k is correct since both traces have a 1k pullup on the core. Did you add the second 1k pullup on the core as described http://ucapps.de/mbhp_iic_midi.html (Sencond image under "Configuration and Interconnections")If you have the resistor in place your total resistance should be ~1500 Ohms (1k in series with 2x 1k in parallel). Quote Link to comment Share on other sites More sharing options...
monokinetic Posted September 15, 2008 Author Report Share Posted September 15, 2008 Hi nILS,I am pretty sure stryd was referring to the IIC board without anything connected to it. In that case the resistance should be infinite (not "no resistance").Aha, OK thanks for clarifying that. I do indeed have infinite resistance on my IIC MIDI board and the bankstick board when removed from the Core. When connected to the Core ~2k is correct since both traces have a 1k pullup on the core. Check! I have 2K between SD and SC on the Core.Did you add the second 1k pullup on the core as described http://ucapps.de/mbhp_iic_midi.html (Second image under "Configuration and Interconnections")Hmmmm, I had referenced this picture when working out how to install the extra MIDI In parts on my IIC board. I am using a MB Core V3 PCB from Mike and my understanding was that this picture is referring to the Core V2 (from the note underneath it). I have R2 and R12 on the Core, so as mentioned previously I have 1K resistance between SD and VD and 1K resistance between SC and VD.If you have the resistor in place your total resistance should be ~1500 Ohms (1k in series with 2x 1k in parallel).So if I understand you correctly, in fact I need one more 1K resistor between SC and VD even though I am using a MB Core V3 (you seem to be talking about 3 resistors in total). Is that what you mean? (sorry if it seems obvious, it's Monday!)TIA for your assistance!Dave mK Quote Link to comment Share on other sites More sharing options...
monokinetic Posted September 15, 2008 Author Report Share Posted September 15, 2008 I had a go at soldering another 1K resistor between SC and Vd, checked that I got 1500 Ohms across the SC and SC lines and tried a few goes but I still have exactly the same problem still :( I also double checked that the bankstick board and the IIC board both have infinite resistance between SD and SC when not connected to the core, individually and connected together on the IIC bus.Any other suggestions? I'm contemplating trying to flash the PIC again, long shot I know but I'm out of ideas!D Quote Link to comment Share on other sites More sharing options...
Futureman Posted September 16, 2008 Report Share Posted September 16, 2008 Just a small thought, but in your sequencer midi options, make sure that "midi clock" is not on for the IIc's... I don't think they can handle spitting out MIDI clock.(I have not verified that it will cause your issues tho)RegardsMike Quote Link to comment Share on other sites More sharing options...
monokinetic Posted September 16, 2008 Author Report Share Posted September 16, 2008 Hi Mike,Thanks for the input, interesting point, it's not something I really thought about! I will have a play with some of the options tonight when I get home from work. You also prompted me to re-read the manual at ucapps and I realised I shouldn't be sending MIDI clock in to the IIC either!However, the behaviour is the same if I send MIDI clock or notes from both my keyboard or my PC sequencer. The IIC Rx LED flashes to indicate that it has received approx 28 events. Then the light stops. Sending MIDI in to the IIC does not control things on the MBSeq (i.e. an arpeggio track etc)I'll see what this evenings fiddling leads to!BestDave mKD Quote Link to comment Share on other sites More sharing options...
monokinetic Posted October 4, 2008 Author Report Share Posted October 4, 2008 Well without wanting to seem like I enjoy talking to myself.......I thought I should post the conclusion of this thread. Which is that I found the problem, I had not connected the extra cable between IIC Midi R1 and the Core J6 SI.So if anyone searching the forum later on comes across the initial problem of this thread, make sure you double check http://www.ucapps.de/midibox_seq/mbseq_v3_interconnections.pdf to ensure your IIC Midi in works ;DI'm off for some experimentation with synchronising all 3 of my sequencers, hurrah!Dave mK Quote Link to comment Share on other sites More sharing options...
nILS Posted October 4, 2008 Report Share Posted October 4, 2008 Glad you got it working! Thanks for sharing the answer! Quote Link to comment Share on other sites More sharing options...
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