Clock Help?

Discussion in 'The Projects Forum' started by mrtonyd, Nov 22, 2010.

  1. mrtonyd

    Thread Starter New Member

    Nov 22, 2010
    5
    0
    I am building a clock using 74161 chips and I feel like I'm pretty far along. I have the seconds and minutes displays working, but I'm stuck on the hours display. The seconds and minutes reset after 59, but I'm having a little trouble getting the hours to roll over. I want the max to be 12 instead of 23. If anyone could help, I'd appreciate it. Thanks
     
  2. mrtonyd

    Thread Starter New Member

    Nov 22, 2010
    5
    0
    The logic to roll over 12 to 01 is really what I'm stuck on. I can't seem to figure out how to roll over from 9 to 0 then 2 to 0.
     
  3. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    Bill_Marsden did create this thread some time ago:
    Digital Clock Block Diagram

    Basicaly you should detect the 13 to load the counters again with 01.

    Bertus
     
  4. mrtonyd

    Thread Starter New Member

    Nov 22, 2010
    5
    0
  5. mrtonyd

    Thread Starter New Member

    Nov 22, 2010
    5
    0
    I almost finished it. I almost have everything working. I got all the times going and rolling over fine, but I am now having trouble setting the time. I have two switches. One sets minutes and one sets hours. The hours set fine, but when I try to set the minutes, it cycles through the ones place and goes into hex before binary. so it goes from 0-9 then a-f and back to 0. If someone could look at my schematic and help me out or something here is a link. I'm not sure if the colors all show up or not, but I can post another in a different color scheme. Thanks
    http://img33.imageshack.us/img33/93/clockbuggin.jpg
     
  6. mrtonyd

    Thread Starter New Member

    Nov 22, 2010
    5
    0
    I have the decoders in the schematic, but aren't using them because I got frustrated having to connect them all, so I just skipped a step and used decoded displays for the schematic purpose. My real one is going to use them, so I thought I'd just throw them on the schematic.
    If you can't see the yellow lines, it's not a big deal. That is just the 5v power line.
     
  7. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
Loading...