Another option is a specialized driver IC.  Maxim has one made specifically
for this purpose.  You clock in data from your microcontroller serially and
it handles multiplexing, refreshes, etc.  Don't recall the part number
off-hand, but you could do a search at <www.maxim-ic.com>.

Another of my $.02 worth,
Adam





lists@HOME.COM on 02/14/99 02:16:07 PM

Please respond to PICLIST@MITVMA.MIT.EDU

To:   PICLIST@MITVMA.MIT.EDU
cc:    (bcc: Adam Bryant/PEAK/MOORE)
Subject:  Re: Routine for display




At 22:28 02/14/99 +1000, Paul B. Webster VK2BZC wrote:
> # What are the four displays?  Multiplexed 7-segment?  Common cathode
>or common anode?  How much current per segment do you want?  Do you want
>to use 8 wires (no DP?), 9, 10, or 12?  Alternately are you using
>latched BCD displays?  Latched ASCII?  Have you designed the circuit
>yet?  Have you decided on the components yet?
now you slightly surprised me. 4 multiplexed 7-segment digits (even without
dp) on 8 wires? without heavy encoding/decoding/latching? i'd understand 9
wires, using a 2-to-4 decoder, but 8?
ge