dhenry:
Here's a way to read a parallel-in/serial-out register with one pin:
Another approach is to use a rc network.
it exposes the transient and incorrect data patterns being shifted in to whatever device is connected to the shift register
Whether that is a problem will depend on the device connected to the shifter register's output. HD44780 for example would have no problem here - see the use of HC164 on those displays.
Hey, I agree with you there, but why not just 164s instead of the 595s if you are not going to use those (extremely useful) latches anyway? They are cheaper at Jameco at least.