74LS595 vs. 74HC595

What is the difference… I was looking for the ‘HC’ in the SparkFun Eagle library. I wasn’t paying attention, and used the ‘LS’ instead. I have basically designed the whole project around it, so are they compatible??

Pin compatible yes; otherwise it depends…

LS is bipolar TTL (“low speed” is the typical moniker), and HC is CMOS (typically faster switching). Sometimes they can be compatible, other times not. A similar discussion:

As always - check the specs to be sure…

:slight_smile:

Well, pins are really all I care about… But on the Board, will it call it a 74LS595, or can I name it something else (74HC595)?

Also… I think the pins on the 74LS595 in the SparkFun Eagle library are wrong…

I just double checked this… I need all of the pins, and the one I found is missing two pins…

But on the Board, will it call it a 74LS595, or can I name it something else (74HC595)?

There are multiple ways to have your PCB call a part whatever you want. You can usually rename it in the Schematic. Or you can “Smash” the part on the PCB, delete the name, and add your own Text.

Also… I think the pins on the 74LS595 in the SparkFun Eagle library are wrong…

I compared the SFE Library’s 74LS595 to the TI Datasheet for the 74LS595 and all of the pins are there. When looking at the Phillips 74HC595 all of the pins are accounted for, though they are named slightly different.

Which pins do you think are missing?

Well, in the built in libraries, I went to 74*595, and looked at the DIL…the pins are not what the ShiftOut tutorial says…

Well, in the built in libraries, I went to 74*595, and looked at the DIL…the pins are not what the ShiftOut tutorial says…

Compare the datasheet for the Philips 74HC595 and the TI 74HC595. Pins functions are the same. The timing diagrams match too. (As you would expect for a standardized part like this.)

The ShiftOut example used the naming convention for one manufacturer and the Sparkfun component used the naming convention from another.

they are the same, HC and LS are just cmos vs TTL technology’s

http://www.interfacebus.com/voltage_threshold.html

Well, I don’t know the pins on mine… Can someone point me to a Phillips 74HC595N Eagle part?

Well, I don’t know the pins on mine… Can someone point me to a Phillips 74HC595N Eagle part?

huh? If you still insist you (somehow) have the only 74*595 part in the world with a different pinout, you can always make your own part. Search google for “sparkfun eagle custom part tutorial.”

For what it’s worth… here is a screen shot comparing the 74HC595’s pinout next to the Sparkfun Eagle part:

Pins 1-7  QB..QH / Q1..Q7
Pin     8  GND / GND
Pin     9  !QH / Q7
Pin   10  SCL / !MR  (clear)
Pin   11  SCK / SH_CP   (shift register Clock)
Pin   12  RCK / ST_CP   (storage register clock)
Pin   13  !G  / !OE   (output enable)
Pin   14  SER  / DS  (serial/data input)
Pin   15  QA / Q0
Pin   16  VCC / GND

So what pins are missing? They are all accounted for in the Sparkfun part.

All 595’s have the same pinout!

Take a look at pin 10… SCL vs. MR… Two TOTALLy different things…

Take a look at pin 10… SCL vs. MR… Two TOTALLy different things…

You really need to read the datasheet.

TI Datasheet for 74LS595: Pin 10 SCL or SRCLR, “Direct overriding clear (SRCLR) input”
Phillips Datasheet for 74HC595: Pin 10 MR, “Master Clear”

Same Pin. Same Function. Different Names.

If you read the description in both datasheets they work the same. If you look at the timing diagrams they are the same.

It is the same thing.

Sorry for being stupid… I am only 12…