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From: mike on 29 Jan 2010 15:53
Joel wrote:
> I've got eight 7-segment displays. I know I've multiplex four at once but
> eight seems like a lot. It'd be slick to need just 16 pins. Can it be
> done?
>
> ---------------------------------------
> Posted through http://www.EmbeddedRelated.com

pay attention to the peak current specs on the leds and
whatever you're using to drive 'em vs. the peak current needed
to get the brightness you want.
From: D Yuniskis on 29 Jan 2010 16:36
Joel wrote:
> I've got eight 7-segment displays. I know I've multiplex four at once but
> eight seems like a lot. It'd be slick to need just 16 pins. Can it be
> done?

Depends on what sort of intensity/brightness you want from them.

8-way mux was commonplace many years ago to economize on
hardware. Often, the display multiplexing hardware
was tied to the *keyboard* multiplexing (e.g., drive a
display digit and a keyboard column at the same time).

Look at the efficiency of your displays (i.e., how little
current does it take to get the brightness you want) and
the maximum current each digit can tolerate (before it becomes
a DED -- Darkness Emitting Diode).
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