All About Circuits Forum  

Go Back   All About Circuits Forum > Electronics Forums > Homework Help

Notices

Homework Help Stuck on a textbook question or coursework? Cramming for a test and need help understanding something? Post your questions and attempts here and let others help.

Reply   Post New Thread
 
Thread Tools Display Modes
  #1  
Old 03-11-2009, 06:24 PM
hitmen hitmen is offline
Senior Member
 
Join Date: Sep 2008
Posts: 156
Default Combinational Logic Circuit to convert Excess 3 code into BCD code

I know that -3 = 0000
-2 = 0001
-1 = 0010
and that 10, 11, 12 are dont care conditions.

But how do I implement the K-map?
Reply With Quote
  #2  
Old 03-11-2009, 09:18 PM
beenthere's Avatar
beenthere beenthere is offline
Senior Member
 
Join Date: Apr 2004
Location: Missouri, USA (GMT -6)
Posts: 15,815
Blog Entries: 10
Default

Make a table of the excess 3 codes and their BCD equivalents. Work from that.
__________________
First comes the hardware, then the software.
Reply With Quote
  #3  
Old 03-12-2009, 11:37 AM
hitmen hitmen is offline
Senior Member
 
Join Date: Sep 2008
Posts: 156
Default

Table ? I dont exactly understand.

-3 = 0000
-2 = 0001
-1 = 0010 (These 3 dont care)

0 = 0011
1 = 0100
2 = 0101
3 = 0110
4 = 0111
5 = 1000
6 = 1001
7 = 1010
8 = 1011
9 = 1100
10 onwards not possible dont care

Where do I go from here?
Reply With Quote
  #4  
Old 03-12-2009, 12:48 PM
beenthere's Avatar
beenthere beenthere is offline
Senior Member
 
Join Date: Apr 2004
Location: Missouri, USA (GMT -6)
Posts: 15,815
Blog Entries: 10
Default

Think of your excess 3 codes being applied as select bits to some multiplexers.
__________________
First comes the hardware, then the software.
Reply With Quote
  #5  
Old 03-12-2009, 01:19 PM
vvkannan vvkannan is offline
Senior Member
 
Join Date: Aug 2008
Location: India
Posts: 137
Default

Hello hitmen,

Set up a 4 variable k-map . The input variables A,B,C,D are the
excess-3 code bits(starting from 0011 ,which corresponds to A'B'CD) . This is for the first bit of all the output values(which is BCD ).

Similarly do it for the other 3 bits which means you will get 4 K-maps in all
Reply With Quote
  #6  
Old 03-12-2009, 03:04 PM
hitmen hitmen is offline
Senior Member
 
Join Date: Sep 2008
Posts: 156
Default

Quote:
Originally Posted by vvkannan View Post
Hello hitmen,

Set up a 4 variable k-map . The input variables A,B,C,D are the
excess-3 code bits(starting from 0011 ,which corresponds to A'B'CD) . This is for the first bit of all the output values(which is BCD ).

Similarly do it for the other 3 bits which means you will get 4 K-maps in all
Hi vvkannan,

I understand how to do the question already. But how do the examiners know whether your answer is right or wrong since there are so many dont care conditions? Also, how can a student verify his answer?
Reply With Quote
  #7  
Old 03-12-2009, 03:48 PM
vvkannan vvkannan is offline
Senior Member
 
Join Date: Aug 2008
Location: India
Posts: 137
Wink

Quote:
Originally Posted by hitmen View Post

But how do the examiners know whether your answer is right or wrong since there are so many dont care conditions? Also, how can a student verify his answer?
First of all i am an undergraduate student and i don't have any experience in correction . I studied this subject last semester.

But yes you are right ,we can have many answers for these type of questions.
We try to get the simplified form which uses the minimum number of gates and incase of dontcares just give them the value which reduces the total number of inputs and gates.
But i think you can have many answers
Reply With Quote
  #8  
Old 03-13-2009, 02:53 PM
hitmen hitmen is offline
Senior Member
 
Join Date: Sep 2008
Posts: 156
Default

undergradate? so am I.
Reply With Quote
Reply   Post New Thread

Tags
, , , , , ,


Related Site Pages
Section Title
Worksheet Boolean algebra
Worksheet Memory devices
Worksheet Digital display circuits
Worksheet Encoders and decoders
Worksheet CMOS logic gates
Worksheet Digital codes
Textbook Encoder : Combinational Logic Functions
Textbook Decoder : Combinational Logic Functions
Textbook Don't care cells in the Karnaugh map : Karnaugh Mapping
Textbook Introduction : Combinational Logic Functions


Similar Threads
Thread Thread Starter Forum Replies Last Post
simplifying logic circuit promage Homework Help 5 11-12-2010 07:52 AM
Circuit to Convert Binary to BCD Diamond Homework Help 10 04-11-2009 10:32 AM
Logic circuit setup, help wanted. HellTriX General Electronics Chat 35 07-17-2008 04:55 AM
How To Convert Binary Code To Bcd And Vise Versa? transgalactic Homework Help 6 05-08-2008 04:38 PM
Design Logic Circuit Help NandoNando Homework Help 2 03-13-2008 11:58 PM

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 01:24 PM.


User-posted content, unless source quoted, is licensed under a Creative Commons Public Domain License.
Powered by vBulletin
Copyright ©2000 - 2014, vBulletin Solutions, Inc.