74HC165 Pinout [RESOLVED]

D Faust

On the 74HC165 (parallel in serial out) datasheet I see pinout labels such as·PL, CE, CP, DS,·Q7, and Q7.· PL, CE, and one of the Q7s· has a line over them.

What do·each of these things stand for?· I understand clock, data, and chipselect, can these be·described in these terms?

Thanks

Datasheet attached

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--DFaust

Post Edited (D Faust) : 11/5/2007 1:06:34 AM GMT

PJAllen

The bar means that those inputs are "active low", they're asserted when low.

There is a Q7 and /Q7, the bar means that it is the complement (opposite)·of the Q7 output.

So, a bar means "not", opposite, or "active low."

·

D Faust

OK, that make sense, but what do the letters mean. (I am planning on using the shiftin commmand)

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--DFaust

Mike Green

Parallel Load
Clock Enable
Device Select
Clock Pulse

There's a table near the beginning of the datasheet that explains the abbreviations.
It's not that I know all this stuff off the top of my head ... I go look at the datasheet.

D Faust

Thanks, that makes sense. Are you saying that you got it from the truth because i couldn't figure that out, except for parallel load. Q7 would be my data line, correct?

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--DFaust

Mike Green

Q7 (from the datasheet) is the serial output from the last stage.
That's what gets connected to the controller as the data line.

I can't really remember all this stuff in detail, not reliably.
It's so easy to look it up these days with web searches and
the Wikipedia. Anyone with some common sense, basic concepts,
willingness to do some searching and reading, can look like a guru
these days.

JonnyMac

D,

If you're going to use the 74HC165 with the BASIC Stamp you can find code and circuits in StampWorks.

D Faust

Thanks, I'm going to try to get it working now.

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--DFaust

D Faust

I worked, thanks!! I wonder why the stampworks book uses /Q, it just makes everything backwards. Oh well. Now for my ADC.

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--DFaust

JonnyMac

Since I wrote StampWorks, I'll tell you: I use /Q output with active-low inputs that are standard on the PDB, as this takes care of inverting the bits for me (i.e., a pressed button = 1); if you're using active-high inputs to the 74HC165 then you should use the Q output (pin 9) instead.

D Faust

OK, that makes sense.

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--DFaust