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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 each 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 details on related page
  • 8-bit shift registers (74HC595 and similar registers)
  • SimVimCockpit© firmware controls all of these display types directly, all program code has been developed from scratch according to technical datasheets of every device, 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 as described below 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.

Direct connection

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 currently only 8 pins from # 30 to # 37 of the controller board can be used (may be extended later for any pin). You can assign them in the configurator, all other pins are not available for direct display control.

Here is connection diagram for MAX7219, the same is for LED drivers/registers. For TM1637 simply connect the "DIN" input to the "T" signal line:

Multiplexed connection

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

MAX7219 LED display driver and TM1637 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 signal lines - "D" (pin #28) and "L" (pin #27) output signals.

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 "T" signal line.

DM13A LED display driver

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. So, you can use one multiplexer to connect up to 16 displays.

Note: the "pull-down" resistor connected to the CLK with a value of ~1...3 kΩ is used to prevent the LEDs from being randomly lit because of 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



8-channel extension

To extend number of 7-segment displays or serial LEDs annunciators that are located in some part of your cockpit, but you don't need more than 8 outputs, you can use 8-channel 74HC4051 multiplexer breakout board.

Note: if you use the 8-bit multiplexer board you should take care about the signal inputs location - it is slightly different from 74HC4067. All bus lines are used the same way as for 74HC4067, except of one address line S3 - it's not used in 8-channel multiplexer.



Configuration

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.


Options

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:


Configuration Optionss

Custom text symbols

You can configure 7-segment indicator to display some custom text (as fixed text or text displayed by conditions) using these 26 symbols (along with digits and dot):

Note: this option is available since ver. 0.9.17 beta.

Text examples:

- "Ch" or "CH" (channel)
- "Pr" or "Pro" (programming..)
- "Err" or "Error"
- You can use upper line, middle line or bottom line (using the "~", "-", "_" symbols)
- Using the "*" symbol you can display degree sign (for temperature).

The text can be a part of the displayed parameter value, configured as shifted text and displayed alongside with parameter value or, it can appear in the same position, replacing the value by condition.

... examples will be added....




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