MobiFlight Community Support

I believe that the Shift Registers are still a work in progress but is there list of which ones are known to work or not work?

I'm working on a G1000 style project and need about 5 or 6 more buttons. I have another 2560 but would hate to use it just for a few more buttons and have to run another USB cable.

Also I saw that the switch limit is 68. Is this because of the number of pins on a 2560 or is that a limitation in MF?

If I use a shift register does the limitation not apply anymore?

The limitation of 68 is because of the number of I/O's of the Mega. Input Shifters are NOT count, so you can increase with them the max. numbers of buttons.
There is a tutorial under https://github.com/MobiFlight/MobiFlight-Connector/wiki/Adding-lots-of-buttons-with-an-input-shift-register
also which part is used.
I have no experience with them, but they seem to work pretty good.

Regards

Ralf

As Ralf say....
the Shifters are logical a own device typ.
So for sure. Basically the used Input elements are also Switches/Buttons.....
But from point of view of Mobiflight we need to split....
A "Button" Device is a button located to a Arduino Pin ( like in the past). those are logical limit to 68 cause there are only 68 Pins overall.
A Button on a "Shift Register" is a different thing.... Also here there will be a Limit ( e.g. max 32 Shift registers per Mega)

So the theoretical Maximum of a Mega can be defined not today.... When we know the Maximum Shifters then we can say extremly....
Max Number of shifter * max number of Buttons per shifter + remaining Pins * 1 Button per pin = theoretical maximul of Digital 1/0 Inputs.