Shift Register

Forum 2005-2010 (read only) Hardware Interfacing
1

I have a question about this product:

(refer to the datasheet)

I want to confirm what the pins are:
SH/LD (line should be ontop): What is this?
CLK: clock
CLK INH: what is this?
SER: Serial in
QH: Serial out
QH: What is this?
A-F: parallel ins
VCC and Ground: Power

Can someone help with the ones I had questions about?

So if I wanted to take readings from 8 buttons as a serial line, I would connect them to A-F, connect my output to QH, and pulse clock. (Correct?)

Also, how would I daisychain them? I bought 3 for a project, and I need all 24 inputs. Would I connect the QH on one to SER on another, getting 3 bytes on the last QH line?

Thanks in advance!

2

FYI - There was this recent thread about a library for 74HC165N - http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1292080975

3

I agree that it isn't clear what the inverted output is useful for?

Think that in the days these chipse were developed even adding an inverter meant another IC, so as the signal was available and there was a pin free it made sense to output it.

4

So if I had 8 toggle switches on A-F, I would power the thing, toggle SH/LD, toggle CLK, and read QH? If i wanted to daisychain, I would feed the output to SER on another shift register. The output of the second one would be two bytes-- the first shift register and the seconds one.