MobiFlight Community Support

I built a new panel and I have a selector switch that I want to use to select different data in a 8 digit LED display, everything is working fine the only problem is that the data I use have different length in digits and decimal points, how can I force to write the new data and erasing (or blank) any extra digit that was there from the previous data ?
Also sometimes in the initialization of mobiflight I have the same problems where some digits shows something and the new data doesn't erase or write that portion.
Thanks for your help.

Hi

You say basicly "everything working fine"
So hopefully i understand right and you still be able to work with the "selector switch" logic ( Custom offset write and a Read config you use for Indicaton later)

So your Problem is just the System you work with.

Please correct me if i´m wrong ....
I expect:
You have a INPUT Config for the Selector Custom Offset. For example if($=3,0,$+1) .... So it swap between 0,1,2,3,0,1,2,3, and so on.
You got a OUTPUT Config that read this Offset .... E.g. named "Position Indicator"
You finaly got 4 Outpuit Configs for the Display..... Each use a individual Number of Diggits. E.g. Config 1 use Dig 1-5 .... Config 2 use Dig 1-3 and so on.
And Each Config use a Precondition like "Only work if Config "Position Indicator = X" ... Like Config 1 if Value =0 .... Config 2 IF value = 1 and so on.

THIS is correct. BUT sure.... It have the exact problem you report.

LEts say Config 1 Use 5 Diggits and show altitude "55555" When you now switch to Config 2 and that use only 3 Digits then a Speed e.g. of 222 is shown as "22255" Cause the "55" on Digit 4 and 5 are still shown. We Disable the "old" config but the new one not use these two Diggits. So they remain in the last status !

Solution:
You must choose for all used Configs ( taht work with that Display) the SAME Diggits ( and also the same Number)
Simply use the largest Number you need.... If you got e.g Configs with 3,3,5,and 6 Diggits then ALL must use 6 Diggits now.

At last you must use the "Left Padding" Function for the shorter Displays, so the look good. Here Typ "Space" is used to Blank the unneded Diggits.... And LEft Padding Yes No is used to define if number is on the Right or on the left of the Display.
******************

Alternate: IF you work with placeholders then you need to rework the values in Compare with additional "spaces" to make them longer. Same Logic! All Values need to get the same length. You just replace the Precondition System with formulas..... But system stay the same.

pizman82,
Thanks a lot, that was exactly my question, I’ll test it tomorrow.
Also I noticed that sometimes the brightness of some of the displays change and on or two have Max illumination, if I re start mobiflight thay return to normal. Any suggestions ?. Thanks.

Also I noticed that sometimes the brightness of some of the displays change and on or two have Max illumination, if I re start mobiflight thay return to normal.

This can have multiple reasons.
Without testing and research ( so seat on your computer/cockpit) i can not check this directly.

Ideas:

1. Broke Max7219
Like every electrical Part.... Also a Max can be broke. If you got another Max7219 you can simply change and test.

2. Elctrical Issue
E.g. if you wire the Displays from Max to Display with a own custom wire logic ( Displays are no longer mount on the Max itself) . Lets say you combine ( whatever why) multiple GRD/DIG wires together.... So a Diggit is light "double" then its brighter then others.

3. Unlucky coincidence
May a lost data signal occure in a change of the Max7219 internal Resistor/Brightness Controller.
Thats a rare issue. Can happen but normaly not.

4. Software issue
I not made this in the past.... Cause this means i would need to make a hard misstake un purpose. But in theory i think a wrong Config Logic could also occure to this.
If two Configs use the same Display same time then it "flickering" In case this is verry fast the flickering is shown as a "darker" Diggit.
So hardly.... If you got bigger issue in your configs and e.g. 4 Digits are Double Set and a 5th diggit is only single set.... Then this 5th Diggit look brighter then the others.
But sure.... This is not normal and you need to make real crazy configs to get this result.



EDIT:
If we not talk about Single Displays.... If we talk about a FULL MAX7219 is involved and you use a Chain of multiple Max Chips in a row....
Then there can be a Power Problem !.
Please Confirm each MAx7219 got a OWN 5v Line.
You can not chain the 5v from Chip to chip..... If you do so you must rework the tubes and remove a Didode on the PCB ...OR... Build a Bypass Wire !

Thanks again for the comments, I have 6 8 digits display in Daisy chain, everyone is power by direct 5 V on the input side, I’m using 5 v from arduino, not external power supply this may be an issue, I’ll check consumptions and also configuration, only sometimes some of them have higher illumination.

hhhm.
In thery this sounds good. Whatever i have no experiencre in those long Chains. I personaly try to make them as short as possible. So in my testing elements the longest chain is 2 Chips in a row and normaly i use only 1 Chip withaut chaining.

I know this is a philosophic question. And i also know for example Stephan still work with a 6 Chip Chain for years and is happy with it.

Finaly just a personal idea.... If you got 3 Pins free and if its not a big deal to rewire your Displays the i would test to set them as 2x3 or 3x2 if you got 6 Pins free.
Sure... Only do this if your in building progress... I would not "kill" a finished and tidy wired element again just for testing. But if Panel is still open and your in testing phase..... Give it a try if you like !



At last about Power.
Here the question is... What is on the board except of the 7Segs.... If there are Motors or many many LED with High Power then it can be a problem.
Simple rule.... All Devices should not overdrive the 500mA Limit. Then there is no problem.
External power is possible but we recommend to not power the Mega..... For Motors power them directly.
The Mega not need external Power aslong the USB support it. MEans if you need more power use a Powerd USB Hub. Then you got garantee 500mA on the Mega and not get in trouble with the PC PSU in a bigger Cockpit that include 30+ Megas e.g.

Thanks for the additional information, I’ll try to split them, with limited experience I agree with you, in initial testing also had issues with noise getting into the power even with the filter capacitor, in any future design I’ll consider that also.