I have a 4 digit LED serial display which came in two-two digit displays soldered together on a board. There are 5 pins off the side:
5v = power
GND = ground
DIN = ?
LOAD/CS = ?
CLK = ?
What do the those mean?
Ultimately I need to build a counter with a student. Basically when a button is pushed it will count on the display. Any help someone can provide would be great.
What chip is on them a max serial driver i bet DIN is data, load is latch and CLK is Clock. But you'll need to see what chip there using may even be a shift register.
which you control by sending ASCII characters down the serial line.
I'm not sure what you mean there, they sound EXACTLY like serial displays to me. A 3-wire serial interface is a very common way of driving lots of digits and I've had good success with things like that using the ShiftOut function. Those sparkfun things are crap anyway. I bought one once, never again.