All About Circuits Forum  

Go Back   All About Circuits Forum > Electronics Forums > The Projects Forum

Notices

The Projects Forum Working on an electronics project and would like some suggestions, help or critiques? If you would like to comment or assist others with their projects, this is the place to do it.

Reply   Post New Thread
 
Thread Tools Display Modes
  #1  
Old 04-21-2010, 08:06 PM
eehelp eehelp is offline
New Member
 
Join Date: Apr 2010
Posts: 7
Default Help with digital clock...

I have to build a digital clock using 74161 counters for my final project, but I'm having troubles. I got part of the seconds to work, but I'm stuck when it comes to the rest of the seconds, minutes, and hours. Here's the schematic of what I have now: http://www.flickr.com/photos/38401311@N05/4541585238/. Thanks in advance!
Reply With Quote
  #2  
Old 04-21-2010, 09:47 PM
retched's Avatar
retched retched is offline
Senior Member
 
Join Date: Dec 2009
Location: Baltimore, MD
Posts: 5,198
Blog Entries: 14
Default

Bill_marsden has a clock diagram you will want to look at. Search the forum for clock circuits and you will find plenty.

Ive found the diagram:
__________________
-rm-
Reply With Quote
  #3  
Old 04-21-2010, 10:55 PM
eehelp eehelp is offline
New Member
 
Join Date: Apr 2010
Posts: 7
Default

I've been looking all over for some examples, but I can't find any. I have to use 74161's for this project unfortunately.
Reply With Quote
  #4  
Old 04-21-2010, 11:01 PM
kingdano kingdano is offline
Senior Member
 
Join Date: Apr 2010
Location: USA, Massachusetts
Posts: 377
Default

the posted diagram, looks to me at least, like an overall architecture that you can use with any device essentially.

what it is showing you is an overall topology to apply to your specific devices.

i think.
Reply With Quote
  #5  
Old 04-22-2010, 12:02 AM
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

Use "74161" as a search term in Google to get a data sheet. That should answer some questions - like how to get the tens part of the seconds counter to go. Onece you have that, everything else should fall into place.
__________________
First comes the hardware, then the software.
Reply With Quote
  #6  
Old 04-22-2010, 01:40 AM
eehelp eehelp is offline
New Member
 
Join Date: Apr 2010
Posts: 7
Default

I looked at the datasheet, but it doesn't really say anything about how to make different counting sequences...
Reply With Quote
  #7  
Old 04-22-2010, 07:24 AM
rjenkins rjenkins is offline
Senior Member
 
Join Date: Nov 2005
Location: Sheffield, England
Posts: 1,015
Default

If I remember correctly, the 161 is a synchronous counter with load.

To do seconds, minutes & hours you would need two stages each.

With each two decade section, you have to use a few gates to give a signal at maximum count (eg. 59) and use that to activate the Load input.

The next clock pulse would then load the value from the input pins (which you set to fixed levels) rather than incrementing the count, so 59 -> 00 or 12 -> 01. (Or 23 -> 00 if you prefer).

If you are on to counters you should understand simple gates, so start drawing you circuit!


ps You have already said it's homework, so no one will design it for you - clues and pointers only.
__________________
Robert Jenkins.
Reply With Quote
  #8  
Old 04-22-2010, 08:59 PM
eehelp eehelp is offline
New Member
 
Join Date: Apr 2010
Posts: 7
Default

Thanks for the advice, but I just really don't understand how to make this work. Could anyone give me more specific advice? I switched my major a while ago, so now I just have to pass this class...
Reply With Quote
  #9  
Old 04-22-2010, 09:23 PM
retched's Avatar
retched retched is offline
Senior Member
 
Join Date: Dec 2009
Location: Baltimore, MD
Posts: 5,198
Blog Entries: 14
Default

http://www.kpsec.freeuk.com/counting.htm

This should help a little.
__________________
-rm-
Reply With Quote
  #10  
Old 04-26-2010, 05:22 AM
eehelp eehelp is offline
New Member
 
Join Date: Apr 2010
Posts: 7
Default

Thanks for the link, it did help with resetting the counter so it only counts to 5. So now for some reason the 2nd counter for the seconds is starting to increment when the first counter gets to 8, instead of 9. Here's what my circuit looks like: http://www.flickr.com/photos/38401311@N05/4553827050/
Reply With Quote
Reply   Post New Thread

Tags
, , ,


Related Site Pages
Section Title
Worksheet Counters
Worksheet Flip-flop circuits
Worksheet Switched capacitor circuitry
Worksheet Digital communication
Worksheet Multiplexers and demultiplexers
Video Lecture Asynchronous Counters - Digital
Video Lecture Counters - Digital
Video Lecture Sequential Logic - Digital
Textbook Introduction : Shift Registers
Textbook Synchronous counters : Sequential Circuits Counters


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 07:00 AM.


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