# Is there a chip that does this?

Posted by Forrest Higgs
 Is there a chip that does this? February 08, 2008 12:09PM Admin Registered: 17 years ago Posts: 1,915
I have a question for an integrated circuit boffin sort of person. I know that there are all kinds logic gate chips that can take two inputs and generate a single output.

Is there, on the other hand, a chip out there that will take one input and generate two outputs. I basically need a chip that for an input A and outputs B & C has the following truth table.

If A = 0 Then
B = 0
C = 1
Else
B = 1
C = 0
Endif

I know that I can build that up with a few logic gates, but I was wondering if there is a single chip that will do that of perhaps a single chip that contains several of these functions.

What I am trying to do is cut down on the number of i/o pins on my PIC that I need to control directional control on the SN 754410 when I am running a bipolar stepper on it.

Thanks
 Re: Is there a chip that does this? February 08, 2008 12:41PM Admin Registered: 17 years ago Posts: 1,915
Okay, nophead says that I need an inverter chip. That seems to solve the problem.
 Re: Is there a chip that does this? February 08, 2008 12:44PM Registered: 16 years ago Posts: 447
Best bet is a hex inverter (6 inverters on a chip). Connect A to the input of one inverter. Connect C to the output of that. Chain that to the input of a second inverter and connect B to the output of that. You'll be able to get 3 of these from a single IC.

Part numbers for hex inverters, depending on your needs:
74LS04
74HC04
MC14069
 Re: Is there a chip that does this? February 08, 2008 12:55PM Admin Registered: 17 years ago Posts: 1,915
Yup, Nop suggested the 74HC04. Thanks, Steve.
 Re: Is there a chip that does this? February 08, 2008 01:34PM Registered: 16 years ago Posts: 447
Ah, he beat me to it. I type too slow.
 Re: Is there a chip that does this? February 08, 2008 01:35PM Admin Registered: 17 years ago Posts: 1,915
You missed it by about 5 minutes, no more.
 Re: Is there a chip that does this? February 08, 2008 05:13PM Admin Registered: 17 years ago Posts: 7,879
No need to chain the inverters. The input load from an HC chip is so small that all the drive capability of the PIC will still be available for your un-inverted signal.

[www.hydraraptor.blogspot.com]
 Re: Is there a chip that does this? February 11, 2008 10:00AM Registered: 16 years ago Posts: 120
You might even get away with something this silly, use any NPN-small signal transistor.

V+
|
/
\ 1k
/
\
|------------ C
| /
| /
A -/\/\--|/
|\
10k | V
| \
|
|
---
-
Sorry, only registered users may post in this forum.