Multiplexing

[MR]

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.

[steve_b]

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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Steve

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

[Chris Savage]

Steve,

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.

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Chris Savage
Parallax Tech Support