If you want to use the '164, you will only need one line for CLK and another
one for DATA, tie all the clock inputs for every '164 together, and the last
output of every '164 to the data input of the next. If you do it fast
enough, you don't even need to shut off the displays while updating.

The way I do it is, with two '164s and four 7447s, and I only use two
microcontroller pins.

Calvin

-----Original Message-----
From: Dr. Imre Bartfai <root@PROF.PMMF.HU>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Viernes 17 de Julio de 1998 1:33 AM
Subject: Re: LED Display driving


>Hi,
>I use daisy-chained 74164's, each for very digit. I need only 2 wire for
>one display. The Pic Basic Pro does it fine with SHIFTOUT command, but it
>is easy to write it in assembly, too. I think for your three groups you
>can connect all the DATA lines, only the CLOCK lines should be separate.
>If you want nice result, you should turn the display OFF whilst updating
>their content. And don't forget the correct CLEAR circuit.
>
>I hope it helps you.
>
>Imre
>
>
>On Fri, 17 Jul 1998, Ali Haydar GOKTOGAN wrote:
>
>> Hi,
>>
>> In a PIC based project I need to drive 3 groups of 8 digits 7+1
>> segment (including decimal point) LED displays.
>>
>> Any suggession will be appreciated..
>>
>> Thanks...
>>
>>
>