Hi Vlad,

#1    I have a MAX7219 matrix board that I am trying to direct connect .  When I open the plug in and select reload configuration I get an error that the name is not recognized and in the box it say "Com1-Size"..

I used the configurator to set up a 737 radio and am using the 6 digit LED as active com 1.

#2  I also want to make sure I am wiring the board to the display correctly.  There are dots on the side of the display, I have the wires on that side going to the matrix board on the side that also has the sing DOT on the in side.  if the DOT is the cathode or Anode side of the LEDs.

all I am getting is some random segments lit up.

2 weeks ago in LEDs, Digital Output by

2 Answers

Hi Les,  Your info is incomplete as to your situation.  1) If you are using the Max 7219 LED Matrix board, but wiring it to a 7 segment display, then you have to select  7 segment direct if using pins 30 - 37 on an AT Mega 2560, you cant use the LED Driver Max 7219 tab to drive the display.  If you want to use other pins then you need an Output MUX between the Arduino and your Matrix Board. Just guessing at your problem as don't know which radio profile was selected.  If you are using a 6 digit 7 segment display that is just the chip then wiring is different than a 7 seg, 6 digit display module, so need more info to help you directly.

2 weeks ago by
Ok then lets try changing the output. Change to the Auto Pilot/FMS map, select the MCP Collins B737-8X.  Select Altitude and assign it to the control pin you are using for the MAX 7219.  I know these data Ref's work so this will show whether it is a connection or a data ref problem.  Dots should turn on and off (randomly) as you change the numbers.

Yes you can ALT + TAB out of X Plane to your browser, SimVim Config window.  Then change your inputs and save the data.cfg (must be named data.cfg) and overwrite the same file in your SimVim directory in X Plane.  drop down the plugins window in X plane, Open simvim config tab and when window pop's up you can reload configuration without restarting X Plane.


Ok, that did not work either.  I must have something connected incorrectly.  Question, on the 7219 MAX board, there is already a resistor, do I need to add resistors to each of the LED lines?  I thought the reason for using this board is to eliminate the extra wiring.

Attached are photos of how I have it hooked up.photos


Hi Les, We'll get this fixed, just heading out for supper but will get out my diagrams later and we'll figure out the wiring.


Hi Les, I have attached link to 3 drawings.  Max7219 pinout, 5 digit 7 segment display and Matrix board pinout.  The top corner of the Max7219 chip with the little dot is pin #1, you can verify this by metering between the chip pin and the Din connector on the board.  Now for the connections to the 7 segment display you will need to verify the pins from the Max7219 to their locations, if you look at the picture of my board, you will see which pin is connected back to the Max Chip.  Yours may be the same but you need to verify with meter between the pin on the Max Chip and the board pin, that way you can then set up the proper wiring.  The 5 digit 7 segment display drawing I attached is from my displays, now you have a 6th digit so if you don't have the proper pin locations on your display this will take trial and error.  Another thing I found is that there doesn't seem to be any standard in labeling of the Dig input pins, you will notice that I have renumbered mine in my drawing as they were backwards.  Note that Dig 0 will be the right most segment of your display regardless what they have labeled the drawing.  So in my example Dig 0 (pin 2 on Max 7219) goes to Pin 8 on my 7 segment display, Dig 1 (pin 11 on Max 7219) goes to Pin 6 on my 7 segment display and so on.  If you assign pin 30 on the ATMega to Boeing 737 airspeed, you can use the speed setting to check for proper segment wiring as you can vary all the segments as the numbers go up by one.  Once you find one of the Dig inputs you can verify the A,B,C,D,E,F,G segments are correct by varying the numbers and making sure the correct segments are lit.  After that the remaining pins will be the other Dig inputs and just try them one at a time till you find the right order.  Record your findings as they will always stay the same, and no you don't need a resistor for this to work.

Cheers, feel free to contact me if you have any further problems


Also just verify that your CS pin is connected to pin#27 on the ATMEGA board and DIN is connected to Pin #28 couldn't be sure from the picture.

Thank You Greg,

   I am out on a trip for the next few days, I will look over the diagrams and trace my wirings when I get home.  I will get back to you with what I find out.  Thank you for your help, I am sure once I get one working the rest will fall into place.

You need to use the latest SimVim version ( .9.51) to get all new radio devices functionality work.
2 weeks ago by
I have the latest software loaded, but still can not get the LED display to work.
I No longer get an error code, but still nothing from the LED display.

Also another question. With the matrix board, I assume I do not have to use pull up resistors as there are already resistors on the board?