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Posts: 1

I am building my home cockpit with Mobiflight to interface with Xplane 11/12. I am using MAX7219 for IAS/MACH field. It shows 3-digit speed this is OK but I could not manage to find how to represent the Blinking A (Overspeed) and B (underspeed). How can I implement this? I reserved a 3-digit for speed and one trailing digit for blinking A/B. But I could not find any dataref which I can get A/B or nothing.
Also, how can I blink a single digit? I was planning to use the brightness setting but it is for all the digits, not just one digit. Is it possible to represent an A with MAX 7219?
2022-09-09 14:18
From: ETSI, Germany
Posts: 5648

Your request include 3 individual Problems.... So lets split them up!

1. Raw Data:
We need for sure a Indication that tell us what our Display have to show. Here every AddOn and Sim is different.
For example PMDG have own Offsets in FSUIPC for the Over and Underspeed Warning.
They are "0" if no warning is there and they can be "1" if the related warning is acitve.

Other AddOns use a String! So The Speed is not a Integer Value like 123 .... Its "Text" So its " 123" (Space at left) in mormal mode and A123 Vor Overspeed.

In easy words.... At first you must know and find out a readable Data from your used Aircraft that tell is if a warning is active and if its Over or Underspeed.

2. Max7219 Font.

With 7Seg Displays chars looks not so good ( Here 14/16 Seg Displays are way better.
for sure we can show AaBb ..... The "B" is at the End a "8" So you need to know if its ok for you.
In case speed can not be 800+ or 80 then "8355" is not confusing.... Maybe a Empty Diggit is usefull so its 5 Diggit "8 123" to have a better seperation from the warning and the speed itself..... or simply use the small "b" to not look like a 8.

3. Blinking
This is not a feature of MF till now ( we working on it and its planned for the next bigger release maybe)
Its still possible by using the "Sim time in Seconds" Variable as a indication.
You can read it with a output config and you use a formula like $%2 .... means this value now is 0-1-0-1-0-1 in a 1 second intervall.
So you can say IF Underspeed indication is ON then show the Timer Value ELSE show 0 ..... And in Compare you say If Value = 1 then "b" else "Space"
Means if underspeed is active it will show a "b" and a "empty space" in a 1 second intervall..... If underspeed is OFF it will show a space at all time.

NOTE: If Over and underspeed are splitted you must take care about double commands....
Use Preconditions to avoid both configs working same time OR include both in one Display configs....
So e.g. If Value = 0 show space, if value = 1 (Underspeed) show b Else (Valuie =2 for Overspeed) show A.

In the future you will have hopefully a more intuitive way to handle this !
Good Luck !
2022-09-11 03:04
Posts: 9
For the B738, the datarefs you are looking for are as follows:

Overspeed indication:

Underspeed indication:

Both of these datarefs are integer values 1 for active and for inactive. The datarefs alternate to the flash rate of the MCP indication.

In the output configuration on the Compare tab, select "Apply comparison to modify the current value"
Then enter as follows in the parameters for Comparision Settings.
If current value is = 1
set it to 8
else set it to {space} Note: This is the actual space character

You can do some other things with the battery master switch, master light test, and display light test to allow the MCP to react exactly as the in-sim display does. Best to look though the posted on Mobiflight in Discord.

2022-09-12 01:01
From: ETSI, Germany
Posts: 5648
Thank You Chris.

Thats the perfect way if this Offset/Dataref already include the blinking itself by alternate 0/1 in the correct speed sequence.

Just NOTE:

As i said above.... In case its a splitted Data source ( One Data for the 8 and another for the A) you can get in trouble in MF

Lets say You use 2 Configs for that.... And both are using the same Diggit (left one of SPD) then it come a conflict ...

Lets say we come to Overspeed .....
The Config for Underspeed(8) will show "0" at all time .... means its compare will say "show Space"
The Overspeed Config now like to show "A" and "space" in a sequence.
In the Moment it like to show the "A" same time the Underspeed still show a "space" .

Result: Display is Flickering !

To solve:
In case of blinking sequence its maybe difficult/not possible. We need to try out.
Underspeed PRecondition .... Only work if Overspeed config is not !=A
Overspeed Precondition .... Only work if Underspeed Config is not !=8

For Static Offsets this work.... maybe the Blinking feature struggle MF here. Please try out !
Good Luck !
2022-09-13 13:16