Jason S wrote:

>I'm working on a project that will need a couple of inputs and around 16
>outputs.  The outputs will change at a few hertz at the fastest.  Is it a
>better design to use an 8-pin PIC and send the outputs serially to a couple
>of shift registers or a 28 pin PIC and use the outputs directly.
>
>It seems like the shift register solution is better design because it just
>feels wrong to waste so many IO pins on something that simple, but the
>larger pic means less components, less soldering,  and simpler software.
>
>

I often use a smaller PIC and a shift register.
For driving lamps and relays I use a UCN5821.
Also provides a degree of isolation from PIC <-> load.
The code to drive the S/R is simple and well worth it.
David...

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David Duffy        Audio Visual Devices P/L
U8, 9-11 Trade St, Cleveland 4163 Australia
Ph: +61 7 38210362   Fax: +61 7 38210281
New Web: www.audiovisualdevices.com.au
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