MobiFlight Community Support

Hi,
Ive recently started using mobiflight with an arduino mega and successfully had running rotary encoders and servos off this board but when i to try run a 7 segment led (following the tutorial exactly) i cannot get it to work no matter what i do. Once uploaded to the mega via settings and the output configured nothing happens when i push the test button.
The 7 segment has the max7219 chip so it should be compatible, i have 2 brand new ones and have tried both with the same result. I have also tried different digital pins on the mega and the wiring incase there was a fault in either of those. I have also checked the connections and solders with a multimeter which is showing no problems with connecting. Any help would be much appreciated for this newbie.

Running mobiflight 7.10, build 20200907
Arduino Mega 2560 compatible
Windows 10 64bit

Hello ,


as running the 7 segments are nearly fail safe, the only thing I can imagine is a fault in your mega 2560 board... if you are sure, that the wiring is correct, voltage is correct (if you have mixed the voltage, it can destroy your max7219), then go for another mega (it's not that expensive) and try it with it..did you get any error message when uploading the mega ? as said, normally it is within minutes to get the 7 segments up and running, which is extremely nice, as in previous times, the 7 segments where really difficult to run, especially when you tried for a custom solution (irs panels, LDG ALT / FLT ALT indicator in the overhead)

keep us up to date !

Hi

At first to avoid a issue in used Offset or so..... Test the Displays by creating a new config Line.... Chosse the Display from the Device List. And on DISPLAY Tab of that Output Config you select all 8 Checkmarks ( activate all 8 Diggits) and then press TEST. ( Not the Test in Main Panel... I mean the TEST in the Display Tab of that Config. )
This should show "12345678" on th Display. Mobiflight is NOT in RUN mode that time... We do this test in STOP mode !

If this not work we get another problem.

1. Check correct Pins are in use....
2. Check sequence of Pins... So CLK, CS and DIN are correctly.

3. As you said check Connections. The most problematic part here are the 5 Pin Bridges on the Left.... If they was still solder when you buy it.... Get sure they use Soldertin in all holes. Cheap Chineese Productos often have only a little solder point on the sides and the middle Pins are fully free.
If you solder them yourself.... Confirm you work 100% tidy and as best you can.
I will say in 95% of issue requests THIS is the problem !

4. Just to get sure you not miss the basic rule.... NEVER connect or disconnet a Max while the Mega is powerd.
The Maxchips must be initialised at startup of the Mega (Power up) . If you connect a Max after this moment... Or if you disconnect and reconnect it.... This will not work.
So.... Get sure the Display is plugged to the Pins and THEN Connect the USB to computer ( Or press the reset Button on the Mega).

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Last Note:
My experience is that maybe 30-40 % of MaxTubes (brandnew) are not working in case of bad solder work. After check and reworking it then 99% work fine.
So i not think your unluck and hit 2 times the 1% fully broke Modules.
Same with Egyptair´s idea.... A broke MEGA or broke Pins are verry verry rare. Sure it can be your problem but i would say no.

So.... Check Solderpoints again... And specialy check Point 4 !

Additional Note:

Hi,
Ive recently started using mobiflight with an arduino mega and successfully had running rotary encoders and servos

You talk about "plural" Servos.... How many ??
maybe we also talk about a Power Problem.
Already a single Stepper-Motor and a couple of high power LED´s can overdrive the 500mA Power Limitation.
So please also confirm your setup is within the limits.... Or for testing clearup the Mega and only test the Displays single to get sure all is ok.