I want to drive four 7-segment displays to display a number with the format xx.xx, so instead of using four separate 7-segment displays, I thought it must be possible to purchase a unit with four digits in one.
I've just found these on SparkFun - four displays in one, however - the pinout bemuses me, there are 12 pins - 4 of which are common anodes, okay. However, the other 8.... well, it seems to me you can only control all four digits at the same time, i.e. only display the same number four times, on each digit? As the same segment section has a common cathode connection to one of the pins?
A single digit display has typically 10 pins yes, 7 for the segments, one for the decimal place, and two for a common anode/cathode - so I was expecting 32 pins just for the segments, not including commons?
So, am I missing the point well and truly - or with that SparkFun display, can I only have the same digit four times over? One of the images seems to show otherwise?
EDIT - It seems all combined displays are like this - http://www.farnell.com/datasheets/677505.pdf
Surely these arn't only for displaying the same digit x 4?
Although, here's a 36 pin version - http://www.farnell.com/datasheets/1519763.pdf but the question still stands about the other ones?