View Full Version : Multiplexing

01-15-2007, 09:02 PM
I have a few 7 seg and 14 seg displays that I am trying to multiplex with transistors. Currently I use the pins on the basic stamp to turn them on and off as needed. I need to free up some pins on the basic stamp 40.

14 pins go to cathodes alphanumeric displays
7 pins goto cathodes numeric displays
13 pins needed for Anode connections

If any one knows of a decoder for 14 seg displays
or a way to turn on each display and turn it off quickly than let me know.

01-15-2007, 09:33 PM
Why not use a serial to parallel chip? Would probably have to use the same transistors.

I know there are display IC's...can't htink of a number right now though!



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Chris Savage
01-15-2007, 11:54 PM

Would the 74HC595 be what you meant? The only thing I can see as a potential problem is speed…Depending on how many digits you’re trying to update it may be better to use a chip designed to multiplex and decode for the digits. Take care.

Chris Savage
Parallax Tech Support