# 16 Segment LED, 4 Digit, Common Anode (4 sets)

I'm trying to make an F/A-18C UFC like this:

Now a while ago I bought 6 x "4 digit 16 segment" LED, which happen to be common anode (DataSheet)

What i am looking for is a way to drive all 4 using the minimum of wires - I guess I prefer I²C (IIC) but will work with what ever I can use

• Note: I tried something with a HT16K33 IC, but apparently that will only work with Common Cathode, so this HT16K33 but its Common Anode version would work perhaps?

Thank you, and please let me know if you need more info, or suggestions to clarify my question

• I thought I could reach another audience, didn't realize that was potentially a no-no Oct 22 '20 at 23:46
• Have you tried searching for LED driver chips? Oct 23 '20 at 9:51
• Yes lots of searching, but I never find one that drives common anode Oct 28 '20 at 2:52

I'd recommend using an MCU (and some external driver circuitry) for this. Each of your displays should be mounted onto a tiny board containing the 4-digit display and one MCU + circuitry. The block diagram of functions would look something like this:

You need 64 bits of RAM for the (4) 16-seg display. That's easy to find in any MCU.

I have added a special "control register." I'd recommend supporting at least one 3-bit control word to specify the desired brightness level (handled using PWM.) The intensity levels will be 100%, 53%, 40%, 27%, 20% 13%, 6.6%, and 0%. You could add bits for features like "blinking" or other ideas. Up to you. But if you don't provide for a special control register, you'll probably regret it.

I think you might consider using a 9-bit serial data word size. (Maybe 10-bit.) If you are willing to break up the 16 bits required for a digit into four 4-bit transmissions, then the idea is that you'd transmit the 2-bit digit-select, the 2-bit section-select (there are four 4-bit parts making up the full 16 bits required for a digit), and the 4 bits of data. In addition, since you need to be able to write to the control word, the upper (or lower) bit of the 9-bit serial data word would specify whether this was a control-word write or a 4-bit write to some part of a digit.

I've included the idea of a $$\\text{CLKSEL}\$$ line. If this is high, then the MCU would generate a master clock as an output on the $$\\text{CLK I/O}\$$ line. If it is low, then the MCU would use the observed clock seen on $$\\text{CLK I/O}\$$ (configured then as an input. ) Thus, you can use this concept to combine two or more 4-digit displays into a single concept. The only thing you'd otherwise need is a way to select the appropriate $$\\overline{\text{LOAD}}\$$ with an external decoder so that when writing data you could make sure the right 4-digit module is addressed.

The $$\\overline{\text{RESET}}\$$ line doesn't have to be brought back to where you control the full system, if you don't want to.

This brings things down to about the four lines you wanted, I think.

You'd need to select an MCU with sufficient I/O lines or else add more circuitry. I'd probably look for one with enough I/O.

Just a thought.

Other than this, you may be able to find an existing LED display controller IC for your needs. (Such as the boutique Maxim MAX6954.) But shopping questions are off-topic. So I'm not going to bother looking one up for you.

• You mean something like this: HT16K33 ? Oct 28 '20 at 2:33
• The Maxim MAX6954 and MAX6955 drives Common Cathode, I need Common Anode... That's the hard part everyone that I find is common cathode Oct 28 '20 at 2:51
• @FedaykinWolf I wasn't suggesting any boutique parts. I was only pointing out that they exist in broad, general terms. I'd design and program my own.
– jonk
Oct 28 '20 at 3:08
• @FedaykinWolf I do love seeing your project!
– jonk
Oct 28 '20 at 3:13