Driving 16 Common Cathode Displays

Other Hardware LEDs and Multiplexing
1

I have a need to drive 16 common cathode displays with Arduino. The segment pins can be driven by common leads, but I need all 16 digits to be enabled individually, so a 7219 wont work. Is there a similar chip that can drive 16 separate digits like this?

The reason is that I have a PCB for the Airbus A320 FCU display section that is designed to work with the original non-Arduino board and don't have the skills to redesign it to use 7219 or similar (wish I did). the PCB has common traces for the segments, but 16 separate pins and traces, one for each display.

This is to emulate the function of another board, not related to Arduino. This board has leads for the segments, and then 16 leads to drive each display. It interfaces with 2 other boards back towards a PC using USB as the interface. I want to try and avoid the cost of all of these boards.

2

2 x 7219?

Or 1 x ht16k33?

More detail needed to answer accurately.

3

Thanks, but 7219 wont work. The PCB I have to interface with has common traces for the segments, but 16 individual pins for the digits. The PCB is part of a flight simulator, and can be found at:

https://www.simucockpit.fr/a320/6-le-fcu-les-efis/

It's the FCU PCB.

It has common leads for 7 segments and 16 individual leads for the digits, 2 groups of 5 and 2 groups of 3. Even if the 7 segment pins were split into 2 groups it still wont work because the traces running to the left serve 6 digits, while the traces running to the right serve 6 digits. I would love to redesign this board to work with 7219, etc, but don't have the PCB design skills. My alternative is to figure out a way to do it with Arduino.

If someone wanted to tackle redesigning this PCB and add a 7219 daughterboard on the back I would be grateful, and able to pay a little bit for the work.

Thanks,
Buddy

4

And my other suggestion is unsuitable because...?

5

Paul,

Thanks you for the help. I'm investigating the HT16k33 now. Your comment indicates that it can drive 16 x 7 segment display? I was unaware of that chip, investigating it with high hopes now.

Thanks again,

Buddy

6

Seems like this is 8 digits with more segments?

7

This schematic may be helpful(tested)!

8

Yes, you are correct. Ht16k33 drives 8 cathodes and 16 anodes. If you can't organise your displays like that, and it sounds like you can't, it was not a helpful suggestion.

Ok, so... 16 cathodes and 8 anodes...

Do you have 11 Arduino pins available? Use 8 pins to drive the anodes. The other 3 drive 2x tpic6c595 shift registers (daisy-chained). The Arduino must do the multiplexing in this circuit.