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MB64 internal midi merger seems not to work.


mikee
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Hello all forum friends.

 

I hope someone can give a helping hand with a little problem of mine:

First I connect my core MIDI out (pin 25 TX) to my soundcard MIDI in.

Next I connect one pot and (giving a swift twiddle) note that the correct midi signal appears via midiox.

Then I set the internal core midimerger to 'ON' via the three menu buttons.
 
Next, I connect a good known working opto coupler (same circuit as MB64 core) to pin 26 (RX) of the core chip.

Finally, I plug a good keyboard into the opto circuit expecting to see note data via midiox.

But do I? Not on your nellie. As soon as I power up my keyboard midiox says:
status; 178, data 1; 0, data 2, 0, channel, 3, event, CC: Bank MSB.

Then the midibox display says "Midi time out, Whats up?"

A question I would dearly love to find the answer to.

I know the core chip recieves MIDI from my keyboard (via the same opto coupler set up), and I know the core is sending MIDI signals whenever the pot is turned, I also know the same keyboard/opto circuit happily drives the MIDI input of my sound card.

Why won't the core merger let me merge stuff? Does anyone have a system with the internal merger working?

It might be of some importance to note that my keyboard sends continuous MIDI 'active sense' messages.

Thanks for any possible comments in advance.



 

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Further to my first post:

 

I have just programmed a pic16f88 and built the old midimerger with these results:

 

midi data from the core is being processed by the new merger, but data from my keyboard still fails to appear at the output. The led indicator for that particular input fails to light at all, the indicator for the input from my core blinks quite happily.

 

In other words all is just like when using the core internal merger.

 

I have tried different values of pullups to drive the input (including 1K2 ohms) although it must be said: the value of 510 ohms suits my sound card perfectly.

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  • 2 weeks later...

It seems that the MIDI output of your keyboard somehow violates the MIDI protocol, otherwise I've no explanation why two (independent) MIDI parsers can't handle the stream correctly and raise an error message.

 

It could also be, that MIDI-Ox is a more tolerant - but for proper merging 100% compliancy is required.

Which MIDI keyboard are you using exactly? And could you please search for alternative MIDI monitors? Maybe one of them displays the MIDI stream in a way which allows to identify the violation.

 

(for the case that you own a STM32 or LPC17 based core: I could give you a monitor which displays the incoming data in text format in the MIOS terminal)

 

Best Regards, Thorsten.

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Thanks TK.

 

I mentioned this in HUIS forum, when replying tou your helpful suggestions, to say that I managed in the end to cure problem.

 

The 'keyboard' is in fact a Technics GK5 organ modified into a full sized piano. The data stream contains active sense messages, these cannot be turned off. I was at the point of taking the output directly from the internal circuitry, when I built your old Pic16f877 filter (I like the chip), and the problem is no more, as the offending messages are ignored. Now I can send note ons from my keyboard, and pot data from you MB64 (Pic16f877a).

 

I am as happy as a butcher's mutt.

 

A thousand thanks for all your help and all that work you have done.

 

Regards

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