Personally I don't like the HC165 much. It lacks, from memory, a set of
strobe latches, meaning that data cannot be shifted in while leaving the
outputs stable. The 4094 or HC4094 is much better.

> ----------
> From:         Justin Crooks[SMTP:jcrooks@WYOMING.COM]
> Reply To:     pic microcontroller discussion list
> Sent:         Wednesday, December 03, 1997 5:22 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      MM74C165 shift registers
>
>         Hello,
>
> I've been experiencing peculiar problems with MM74C165 parallel-in
> serial-out shift registers.  I am using the clock inhibit line to
> select a
> set of shift registers, and clocking in the data.  This works
> beautifully
> UNLESS the shift register has some unused parallel-in bits.  I've
> tried
> everything... tying them high, tying them low, tying them via a
> resistor
> bank to Vcc or Gnd, but the only way they seem to work is if I let
> them
> float.  Otherwise the chip outputs a '1' when not selected.  Does
> anyone
> have any ideas to explain this?
>