12-hour digital alarm clock using ttls

Discussion in 'The Projects Forum' started by bobon721, Oct 9, 2011.

  1. bobon721

    Thread Starter New Member

    Feb 8, 2011
    18
    0
    I'm currently working on a digital alarm clock project. Programmable ICs are not allowed. I'm planning to use only TTLs because it's all I have and all I can get. My problem is that I don't know how to force the clock to display 12:00 instead of 00:00. I also have no idea how to implement an alarm that can be set and reset, as with the time. Can anyone provide some insight? Thanks. I have my schematic attached.
     
  2. elec_mech

    Senior Member

    Nov 12, 2008
    1,513
    193
    Hi bobon721,

    This thread may offer some insight:

    http://forum.allaboutcircuits.com/showthread.php?t=59569

    Just look up 7400 series equivalent ICs for the CD4000 series ICs if needed.

    What are you using to provide the one second clock signal?

    I can offer help with a schematic and troubleshooting an actual circuit, not so much for a simulation though. In your schematic however, I notice you have a 50MHz clock signal going into the seconds counter (U2). This should be 1Hz if you're trying to simulate a clock.
     
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