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Many decimal numeric indicators used in real airplanes can be replicated in your home cockpit using 7-segment LED modules, which can be a pretty realistic substitute, especially if you can find indicators with right size and color.

In SimVimCockpit you can choose what type of control is most suitable for every of your 7-segment indicators, any display can be made using:

  • LED display driver MAX7219 - assembled 8-digit modules or custom-made displays
  • LED display driver TM1637 - 6-digit and 4-digit modules
  • 16-bit LED drivers (DM13A and similar, see deteils on related pages)
  • 8-bit shift registers (74HC595 and similar registers)
  • SimVimCockpit© firmware control all of these display types directly, all program code has been developed from scratch, without using any libraries.

You can assemble displays yourself (how to make any 7-segment display), with any number and size of digits, using the DM13A LED drivers, shift registers, or MAX7219 driver.

Also, there are various pre-assembled modules on the market, with MAX7219 or TM1637 drivers, or modules with 74HC595 registers - you just need to connect display module to one of the 16 output and configure what to display on it and how.

Each connected display can consist of up to 8 digits and be used to output 2 or 3 parameters simultaneously when one parameter value is shifted relative to the other.


Every 7-segment display can be controlled by one output of the multiplexer board (0..15). You need to connect the "CLK" input to the multiplexer otput that you have assigned for this 7-segment display in the configurator.

MAX7219 LED display driver

Each display module build on MAX7219 driver has 3 input control signal (besides power lines) - CLK, DIN and CS. The "CLK" input is connected to assigned multiplexer otput, two other signal inputs - "DIN" and "CS" - should be connected to the corresponding common bus lines - "D" (pin #28) and "L" (pin #27) output signals.


TM1637 LED display driver

Display module build on TM1637 driver has 2 input control signal (besides power lines) - CLK and DIO . The "CLK" input is connected to assigned multiplexer otput, the "DIO" input is connected to the common "T" line of the bis.

DM13A LED display driver

This is very convenient way to make any 7-segment display with any number of digits and digits size. This is very convenient way to make any 7-segment display with any number of digits and digits size. With one driver you can make a 2-digit display, with two - 4-digit etc. All connections are the same as for the MAX7219 driver listed above.

Note: the "pull-down" resistor connected to the CLK with a value of ~1...3 kΩ can be used to prevent the LEDs from being randomly lit on power ON and interference between different displays connected to one multiplexer.

Read more information about 7-segment displays types and how to built any display yourself on this tech guide page

Connection options

You can use "direct" connection if needed, without multiplexer. The "CLK" input in this case should be connected to assigned controller pin (no need to use a pull-down resistor), other signal inputs - as described above.

Note: for direct connection only the pins from # 30 to # 39 of the controller board can be used. You can assign them in the configurator, all other pins are not available for direct display control:



The configuration is unified for all displays, you'll only need to select display type and some additional options. All listed parameters are pre-configured for output in the right format, with dot position, number of digits and some of the display options pre-defined.


Any display can be easily configured to output more than one data value. For example, you can have 2 or 3 independent data on one 8-digit display. In the picture above you can see Bus Voltage + Bus Load on the right TM1637 display and DME distance + DME time on the upper MAX7219 display).

To output additional data on the same display, you need to select second parameter, then select the same display number as for the first parameter was assigned, and enter shift position number.

Configuration Examples

Example 1 - Two 5-digit TM16637 displays are connected to the multiplexer outputs #4 and #5 and configure to output of Com1 active and Com1 standby frequencies in 5-digits format.

One MAX7219 display is connected to the MUX output #10 and configured for output of 2 batteries voltage (one value is shifted by 4 positions left):

Example 2 - configuration of "Com1 active" and "Com2 active" displays, connected without multiplexers (controlled pins #32 and #35). One display is MAX7219, for another one the DM13A drivers are used:

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