John;

First, I'm not sure what ou mean by a 4Hz clock.  Most digit multiplexing is
done over 30Hz.  This refers to the digit to digit scan rate.  You should
take care not to go too high, though, since changing digits takes some time,
and if you go too fast, a larger and larger portion of your time is spent
changing and not displaying.  The displays sure have no flicker left in
them, but the brightness will then fall off.  I like to set a byte for scan
rate in software and let timer0 run the scan.  Then I tinker with the scan
value to get the best quality scan.  Scientific, huh?

Chris Eddy
Pioneer Microsystems, Inc.


>This might sound like a stupid question, but at what speed can i drive
>7segment displays?? In my current analogue design i use a 4Hz clock to
pulse
>the displays, but using a pic this is a little difficult.
>
>Will the 7segment display anything at all if i switch them at say once
every
>100 instuctions ( on a 10 Mhz clock )? I suppose it all depends on the duty
>cycle.
>
>Also, do i have to connect anything to the two clock lines in a 16c84 if im
>using the internal clock ?
>
>Thanx
>
>  John