Pages: [1]   Go Down
Author Topic: 74LS595 vs. 74HC595  (Read 3852 times)
0 Members and 1 Guest are viewing this topic.
Somewhere in Arizona
Offline Offline
God Member
*****
Karma: 0
Posts: 725
Arduino must be a drug, because I'm addicted!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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??
Logged

Phoenix, Arizona USA
Offline Offline
Faraday Member
**
Karma: 36
Posts: 5519
Where's the beer?
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

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:

http://www.electro-tech-online.com/general-electronics-chat/8876-hc-vs-ls-integrated-circuits.html

As always - check the specs to be sure...

 smiley
Logged

I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

Somewhere in Arizona
Offline Offline
God Member
*****
Karma: 0
Posts: 725
Arduino must be a drug, because I'm addicted!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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)?
Logged

Somewhere in Arizona
Offline Offline
God Member
*****
Karma: 0
Posts: 725
Arduino must be a drug, because I'm addicted!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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

Somewhere in Arizona
Offline Offline
God Member
*****
Karma: 0
Posts: 725
Arduino must be a drug, because I'm addicted!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I just double checked this... I need all of the pins, and the one I found is missing two pins...
« Last Edit: October 23, 2010, 02:24:42 am by Jeremy1998 » Logged

Austin, TX
Offline Offline
Faraday Member
**
Karma: 64
Posts: 6055
Baldengineer
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
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.

Quote
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?

Logged

Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

Somewhere in Arizona
Offline Offline
God Member
*****
Karma: 0
Posts: 725
Arduino must be a drug, because I'm addicted!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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...
Logged

Austin, TX
Offline Offline
Faraday Member
**
Karma: 64
Posts: 6055
Baldengineer
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
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.
Logged

Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

SE USA
Offline Offline
Faraday Member
**
Karma: 40
Posts: 3783
@ssh0le
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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

http://www.interfacebus.com/voltage_threshold.html
« Last Edit: October 23, 2010, 12:58:25 pm by Osgeld » Logged


Somewhere in Arizona
Offline Offline
God Member
*****
Karma: 0
Posts: 725
Arduino must be a drug, because I'm addicted!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Well, I don't know the pins on mine... Can someone point me to a Phillips 74HC595N Eagle part?
« Last Edit: October 23, 2010, 01:19:16 pm by Jeremy1998 » Logged

Austin, TX
Offline Offline
Faraday Member
**
Karma: 64
Posts: 6055
Baldengineer
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
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:


Code:
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.
Logged

Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

Portugal
Offline Offline
God Member
*****
Karma: 5
Posts: 962
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

All 595's have the same pinout!
Logged

Somewhere in Arizona
Offline Offline
God Member
*****
Karma: 0
Posts: 725
Arduino must be a drug, because I'm addicted!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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

Austin, TX
Offline Offline
Faraday Member
**
Karma: 64
Posts: 6055
Baldengineer
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
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.
Logged

Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

Somewhere in Arizona
Offline Offline
God Member
*****
Karma: 0
Posts: 725
Arduino must be a drug, because I'm addicted!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Sorry for being stupid... I am only 12...
Logged

Pages: [1]   Go Up
Jump to: