Hi
I'm not sure how you want to use a display card with LEDs?
You're wiring the LED bar as if it was a 7 segment digit and send an "8" to it so all LEDs light up? If so, I will not add that, this is just not a "normal" operation.
I'd personnaly use a relay or an optocoupler to allow having enough current in the LED bar, using only one output as well.
JL