On Sat, Jun 08, 2002 at 05:59:39PM -0400, Sid Weaver wrote:
> Does anyone know for sure how many 595s I can daisy-chain together ?

It depends. The fanout is coupled to the clock pin. The propagation delay
of the clock signal depends on the charactaristics of the clock line and the
input capacitance (3.5 pF typical). The datasheet gives no minimum propagation
delay between the serial clock and the serial output.

You need to be able to drive the serial clock fast enough from end to end
so that each and every part clocks before the serial output changes.

I'm sure that with power transistor clock drivers and line termination, that
it would be possible to drive a huge number of parts without a problem.
In addition if you do start to run into propogation problems all you'd need
to do is divide the clocks lines into segments and drive a segment at a time.

So there's no cut and dried answer.

How many parts do you need to clock?

BAJ

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