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Old 05-05-2016, 07:43 AM
daddylops daddylops is offline
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Location: Melbourne, Australia
Posts: 4
Question Momentary vs Latching vs Rising / Falling Edge Sysex Help

Hi all and thanks for your help and time in advance.

I have Momentary switches that I want to act as Latching switches that produce a response (in my Looperlative LP1 Looper) on only the DOWN press.

I've tried my hardest to figure this out including searching threads and reading manuals etc...

I don't fully understand the depths of the different hex codes and their functional equivalents so I've been using an online sysex generator found at


and trial(ing) and error(ing) without success.

I finally hit on this thread;


and by using mode 4C and programming the Rising Edge to have a CC 127 value and Falling edge to have a CC 0 value I've achieved an acceptable (although not 100% consistent) response out of the LP1 although I'm not sure this is the best way to program the MidiCPU.

I would prefer it if I was sending Program Changes not CC messages.
But I could not get a Program Change message to activate the LP1 JUST on the down press and NOT on the release.

I really want to understand the hex code behind the function and am hoping someone might make this clearer, or point me to a resource (the MidiCPU manual did not work for me so far).

Is a Falling Edge the DOWN press of a momentary switch and Rising Edge the RELEASE of a momentary switch? Or vise versa? And what does this physically look like e.g. a sine wave? Or an electrical short etc...? An analogy for this I can visualise?

I thought the Toggle CC mode would suit making a Momentary act like a Latching switch but I could not make it work...

I felt like I wanted a Toggle Program Change mode which does not exist?

Could someone please explain this idea to me as I hope to program the MidiCPU consciously without stabbing in the dark or relying on the online generator.

Thank you all so much.
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Old 05-10-2016, 10:22 PM
Synthetech's Avatar
Synthetech Synthetech is offline
Join Date: May 2012
Location: USA
Posts: 711

Hi, maybe I can help.

The MIDI CPU when set up as a switch on a terminal will read a high signal (5v) until you ground the terminal with the switch by pressing it down. Then it will read Low or Ground.
When you let the switch go and it opens up again it becomes a high signal.

So when you press it down it reads a falling edge and when you let it go it reads rising edge.

Maybe I can steer you in the right direction if I knew exactly what you are needing to send out to your unit.

We can toggle CC to be value 127 the first press, then 0 the 2nd press, then back to 127 and so on...

Program Changes typically are not toggled. I could make a switch do PC 20 when pressed and PC 63 when released, for example.

There are other tricks using layers and register manipulations.. A register stores a number, then we alter the number by adding or subtracting a value to it on the Down press of the switch and then do the PC or CC msg with the new value from the manipulated register upon releasing the switch.
So we could say start with PC 1, then add +1 so the next time it will be PC2, then 3, 4, 5...

Like I said, I would need very exact values of the CC or PC numbers and values needed to msg out to your Looper to help you code it.
Do you have the latest version of the manual? Should be 1.4, not the old 1.2 to do the latest tricks.
Also you should update your CPU to the latest 1.4beta firmware.
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Old 06-29-2016, 10:58 AM
daddylops daddylops is offline
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Join Date: Nov 2015
Location: Melbourne, Australia
Posts: 4

Thanks Synthetech, that is a lot clearer now and enables me to consciously do some of the sysex now.

Specifically I want Terminal 01 to send a PC 01 when the corresponding foot-switch is depressed so on the falling edge, and then nothing on the rising edge.

If this is not possible then an alternative is to have a PC 02 on the rising edge and I can program the Looper to do nothing when receiving PC 02 - however this effectively halves the number of possible PC numbers I can have?

If the first option is possible then I would extend the code out into the other terminals e.g.

T2 = PC 02 on falling edge, nothing on rising edge
T3 = PC 03 on falling edge, nothing on rising edge

Could you please offer some sysex code for

T1 = PC 01 on falling edge and no message on rising edge?

Thank you
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falling, latching, momentary, rising, sysex

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