I see in the documentation you can not "daisy chain" MAX7219 LED displays. From what I understand, if I want to use 2 or more, I need to assign a pin (CLK) for each display. If that is true:

Pin #27 "L" is shared between the 2 MAX7219s

Pin #28 "D" is shared between the 2 MAX7219s

Pin #30 (CLK) for 1 MAX7219

PIN #31 (CLK) for 2nd MAX7219

My Config:

[Devices]
N30 D=0 B=1,10 b=0
N31 D=0 B=1,10 b=0
[Output]
N31    Nav1_Active       o=2
N30    Nav1_Standby    o=2

When x-plane loads, I see they display correctly:

Once I change the stand-by freq, the second MAX7219 gets screwed up:

My question is, do I need a 74HC4051 8-Channel Multiplexer board or am I doing this incorrectly?

** EDIT **

I was able to get this working by double checking my connections. I also noticed you can't turn the encoder too fast or its screws up the display. Nevertheless, pretty cool how it all works with relative ease. 

closed with the note: Issue was wiring
Sep 18, 2019 in 7-Segment Displays by

1 Answer

 
Best answer
Eventually, all such problems for most cases was in wiring and power source quality. The encoder should NOT influence the display.
https://simvim.com/tips_wiring.html
https://simvim.com/tips_power.html
Vlad
Sep 21, 2019 by
Thanks - you are 100% correct.
vlad, noticed in the new version of configurator, there is no option to specify brightness when u have a pin assigned as a multiplexer output + a 7 segment display is setup for one of the 15 subpins.  By default, this is what i see in the data file

N30.4 D=10

Using feedback from above, I manually added the following parameters and the display is now working correctly.  Has something changed recently?

N30.4 D=10, B=1,10 b=25

can you also remind me what is the D, B and b parameters - i assume the b parameter is for brightness.  Should they be seperated by a comma?
We will rework this feature soon.
Vlad
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