It is currently Thu Sep 20, 2018 6:51 pm

All times are UTC - 7 hours





Post new topic Reply to topic  [ 9 posts ] 
Author Message
PostPosted: Mon Sep 10, 2018 12:23 pm 
Offline

Joined: Sat Aug 25, 2018 7:21 am
Posts: 20
Hi all.
I've been brushing up my skills in electronics (mostly combinational logic) in order to facilitate my understanding of the NES PPU documentation (also I really like the topic) and for further study I think CAD tools might come in handy. I've been reading about certain tools capable of transforming truth tables in combinational circuits. However I didn't manage to get it working. I have Proteus installed. Does it have this option? If not, is there any similar software for Linux? (It's ok if I have to use Windows but I'd rather not).

PS: I know there are tools for simplifying bool logic, but I also want the resulting circuit, so I can check my own solutions and advance faster.


Top
 Profile  
 
PostPosted: Mon Sep 10, 2018 7:13 pm 
Offline
User avatar

Joined: Fri Nov 19, 2004 7:35 pm
Posts: 4076
Don't remember the exact name for this, but the OR of a bunch of ANDS and NOTS will give you something which will work, though not necessarily simplified.

Example: XOR
A|B| A ^ B
------
0|0| 0
1|0| 1
0|1| 1
1|1| 0

Because there are rows for 1,0 and 0,1, you can say (A & !B) | (!A & B).

Another example:
A|B|C| A^B^C
----------------
0|0|0| 0
0|0|1| 1
0|1|0| 1
0|1|1| 0
1|0|0| 1
1|0|1| 0
1|1|0| 0
1|1|1| 1

Since any of these clauses will give you a 1, you OR them together.
(!A & !B & C) | (&A ! &B & !C) | (A & !B & !C) | (A & B & C)

_________________
Here come the fortune cookies! Here come the fortune cookies! They're wearing paper hats!


Top
 Profile  
 
PostPosted: Mon Sep 10, 2018 7:18 pm 
Online

Joined: Sun Apr 13, 2008 11:12 am
Posts: 7532
Location: Seattle
I never knew there was any option other than playing with Karnaugh maps.


Top
 Profile  
 
PostPosted: Mon Sep 10, 2018 11:38 pm 
Offline
User avatar

Joined: Fri Nov 12, 2004 2:49 pm
Posts: 7517
Location: Chexbres, VD, Switzerland
Dwedit wrote:
Don't remember the exact name for this, but the OR of a bunch of ANDS and NOTS will give you something which will work, though not necessarily simplified.

The exact name for this is "minterms".
There's two ways to do it, with minterms by summing (OR-ing) AND functions, and with maxterms by ANDing OR functions.

Quote:
I never knew there was any option other than playing with Karnaugh maps.

Karnaugh maps are used to simplify the equation, so that there's less gates involved for the same work. However they are not required per-se.


Top
 Profile  
 
PostPosted: Tue Sep 11, 2018 1:12 am 
Offline

Joined: Sat Aug 25, 2018 7:21 am
Posts: 20
I think the post title wasn't clear enough, although it's detailed in the post itself. Thank you for your answers but I already know the concept of logic sufficiency and how to simplify truth tables by hand using Karnaugh maps. It's the first technique I learned. I'm looking for a software capable of automatically doing this, such as Minilog (Espresso). It would be great if Proteus had this option, as I already have this software installed. So I want to know about a software with this capability, preferably for Linux.


Top
 Profile  
 
PostPosted: Tue Sep 11, 2018 2:12 am 
Offline
User avatar

Joined: Fri Nov 12, 2004 2:49 pm
Posts: 7517
Location: Chexbres, VD, Switzerland
You should look for logisim.


Top
 Profile  
 
PostPosted: Tue Sep 11, 2018 2:34 am 
Offline

Joined: Sat Aug 25, 2018 7:21 am
Posts: 20
Bregalad wrote:
You should look for logisim.


Thank you. That's what I was looking for. I read Multisim is a more suitable version for professional designers. I'll go with Logisim for the moment. Doesn't Proteus have logic optimization capabilities as well?


Top
 Profile  
 
PostPosted: Tue Sep 11, 2018 5:01 am 
Offline
Site Admin
User avatar

Joined: Mon Sep 20, 2004 6:04 am
Posts: 3556
Location: Indianapolis
HastatusXXI wrote:
Doesn't Proteus have logic optimization capabilities as well?


Not that I've ever seen. Closest thing in name at least, is the "gateswap optimizer", but that's just for automatically swapping which NAND gate is used on a 7400, for example.


Top
 Profile  
 
PostPosted: Tue Sep 11, 2018 5:25 am 
Offline

Joined: Sat Aug 25, 2018 7:21 am
Posts: 20
Memblers wrote:
HastatusXXI wrote:
Doesn't Proteus have logic optimization capabilities as well?


Not that I've ever seen. Closest thing in name at least, is the "gateswap optimizer", but that's just for automatically swapping which NAND gate is used on a 7400, for example.


Ok, then. Thank you. It's kind of curious how such a complete CAD software lacks this apparently basic feature.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group