MobiFlight Community Support

Hey. I am trying to use a MAX 7219 chip togheter with 4 digits 7 segment.
I managed to connect all the pins and all the segment work, its even reacts to arduino with mobiflight but it wont show the correct info. For example:

This one should display the current UTC hours which is 10, instead it shows this:


All the segments are working! It happens only after I send a command from MobiFlight.

I have connected a MAX7219 with 7 segment display module like this one:



And it works perfectly, but I only need 4 digits so I want the chip and the displays to be sepretly.

Just for the record I dont have capicators right now, they are on their way from Ebay, maybe thats the casue of the problem?

Does it work in Test Mode? Or does it always show the dashes and points?

Yes. it works in test mode, it looks like as it is in the picture.

So that would mean that is does not work because it should show "8765" instead.
Probably you have to check your wiring.

I tried to rewire it for about 5 times... I will try again..

OK, after another rewiring it still wont work properly. When I hook the arduino to the computer it shows 8888... It seems that something with the communication is broken..

Can you sketch your wiring and share it? Are both GNDs connected to the same GND?

I am using the instructions found here: http://www.learningaboutelectronics.com/Articles/Max7219-4-digit-7-segment-LED-display-driver-circuit.php


The ground pins are connected to 2 different ground pins on my Arduino Mega. I had this problem when they were connected to the same ground source too...

Which digits have you assigned for this module in the MobiFlight ConfigWizard and which digit outputs are you using on the MAX7219?

Pierre

Hey. I tried sever combinations of output digits. All of them are digital. In the MAX7219 I am using 1 for DIN, 12 CS and 13 for CLK.

1 is 11? Because 1 should not be usable in the UI since it is a special Communication port.

As you can see here:
http://i1.wp.com/tronixstuff.com/wp-content/uploads/2013/09/MAX7219_pinout.jpg

Port 1 on the MAX7219 is used for DIN which should connect to Arduino.

Hi, you used a normal 8-digits led module and it worked. So it's a problem with your own circuit. Disconnect all wires and rewire it. Use a multimeter to check all your connections.
Take another MAX7219 to see if the chip is broken.

I tried a different chip and I got the same resault. Maybe the display is broken. I got more on the way from Ebay..

Have you confirmed that you 4-digit-displays are compatible? The must be Common Cathode.