Need help with cascading timers

Discussion in 'The Projects Forum' started by Babae, Mar 26, 2014.

  1. Babae

    Thread Starter New Member

    Feb 4, 2014
    I am trying to implement a timer that counts a multiple of assigned times T1, T2, T3,...,TN. I am using 74F269 8-bit binary counters.

    Basically, I want to cascade N counters so that the first counter counts to T1, then the second counts to T2 and so on. The times T1 to TN do not have any patterns so I pretty much have to load the times to the counters. I am having trouble figuring out how to implement this.
  2. wayneh


    Sep 9, 2010
    Can you share the bigger picture of what you are trying to do? At some point a microprocessor might be a better solution.
  3. Babae

    Thread Starter New Member

    Feb 4, 2014
    I am using the TC signals from each of the timers as interrupt or external trigger signals for some RF equipment and DAC boards. The scope of my objective is quite specific. Right now I have 3 devices to trigger, so I'll need to count T1, T2 and T3. There is also constraint that TC1, TC2 and TC3 signals must happen sequentially so I can't just run the timers in parallel. I suppose I can just have 3 timers that counts T1, T1+T2 and T1+T2+T3 and have them run in parallel? But as a learning experience, I'd rather like to know if it is possible to have the counters count sequentially.
  4. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
    It is. Each counter can enable the clock into the next counter. But other things are possible also. What is the time period for the entire T1 T2 T3 cycle? And what is the timing resolution you need? An alternate non-uC approach is one big counter with three comparators picking off single clock cycles. Three sequential 8-bit periods is less than one continuous 10-bit period.