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Posts: 2
Hi all!. First of all. Thank you for your great MobiFlight.

Let me introduce. During March 2020 I started to build my own MultiRadio with Arduino + Link2fs. It worked like a charm with FSX but I moved to MSFS and as you might know link2fs is not compatible anymore and it is not being updated since a lot.

That´s where´s the awesome MobiFlight appears.

My hardware was done thinking in Arduino, so for example, my 4-pos Rotary Switch for COM, NAV, ADF, Xponder select has 10k´s resistors attached to every of the GND cables. I tried it with MobiFlight but found to many issues when switching between the modes. Many detents are taken wrongly. With the help of the logging; I found that when swtching very very very slowly from pos1 to pos2 and back, it works OK. But when going from 2 to 3, it reads the value of 1 or maybe more values in a sort of chain.

I went back to Arduino and created a simple Sketch for the rotary switch by just reading the pins. Again, it works perfectly.

Seaching in the forum I found that resistors are not needed for MF Boards as pull-up resistors are activated by default for the inputs, and i think thats my problem. But i also have a pushbutton with a 10k resistor on GND and it works perfectly with MF. Clicking on it at in insane speed showed no errors, no bouncing or missed clicks. :mad:

So, my question. Is there any way to enable/disable the pull-up resistors from the board by MF software to test my rotary switch before attempting to desolder my resistors?
Why my pushbutton works Ok with resistor attached and not my rotary switch?

Thanks in advance.
Cheers from Argentina.
2021-04-04 19:01
From: EDDG, Germany
Posts: 1687
Hi sebawrz,

welcome to MobiFlight!

You are right, MobiFlight does not need any resistors in the GND-lines. The only resistors you need are the line resistors for LEDs.
You should remove the resistors in the ground lines or rewire them with wires withoude resistors.
It is not possible to deactivate the internal pull up resistors by the firmware because the firmware has been deliberately set up in this way.
2021-04-04 22:25
Posts: 2
Thank you Stephan for your quick reply.
What a shame, soldering and de-soldering is the worst part of this! :thumbdown: Anyway, i´ll do!
My only concern/doubt is about the pushbutton still working with the resitor attached at the GND line.


It is not possible to deactivate the internal pull up resistors by the firmware because the firmware has been deliberately set up in this way.

Maybe it would be a very good feature for a future release. :)
2021-04-05 23:15