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Help with 7 seg display


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I need some help with hooking up a 6 digit 7 segment display to a Arduino Nano.

Since I'm pretty incompetent at this I'm having trouble finding the correct info.


First question!

I've hooked up "Dio, SCK, RCK" to pins D10-12 on my Nano, is that correct?

5V and GND are hooked up to those pins.


Second question.

The display is using a 74HC595 Driver chip, what information do I need?

I'm guessing the datasheet?

I'm completly lost on this, I've found some sketches but I've not found any with 6 digits.


If anyone would point me in the right direction I would be very grateful!


I'm going to use it as the Viggens CK37 display, so that is step two...





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I'm guessing it's helpful even with "non-supported" modules?


No, it's not. (Unless all you need is position, altitude and heading information.)


That said, adding Viggen support to DCS-BIOS is probably easier than writing your own middleware from scratch. I hope to make that process even easier in DCS-BIOS 2.0, but that's still a few months or more away.


The display is using a 74HC595 Driver chip, what information do I need?


The 74HC595 is a serial-in, parallel-out shift register. SIPO shift registers are a popular method to control many outputs with only three I/O lines (data, clock and latch). The first thing you should read up on is how shift registers work. I'd suggest looking for an Arduino-focused tutorial on the topic.


The datasheet for the 74HC595 might be worth a look too, but it's mostly relevant when you are designing the circuit to look up pin locations and electrical characteristics (such as supply voltage or if the shift register can supply enough current to drive the display).


Next, read up on 7-segment displays and figure out whether your display is a common-anode or common-cathode setup. Then read up on multiplexing 7-segment displays (my guess would be that your board is set up to light up one digit at a time).


Once you understand shift registers and 7-segment displays, you will need to know which signal from your display connects to which shift register pin. If you don't have a schematic of your board, use the continuity buzzer on a multimeter (together with the datasheets for the 74HC595 and your 7-segment modules to look up pin locations) to figure it out.


Now you should be able to write a simple sketch that lights up a single digit on your display.


At that point, you can look for a library that does the multiplexing for you. The following links look like they might match your use case:




If you want an easier way to control 7-segment displays with an Arduino, look into a module with a MAX7219 chip and the LedControl library. The MAX7219 chip takes care of multiplexing up to 8 7-segment digits. Like shift registers, multiple MAX7219 chips can be daisy-chained.

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