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4536 Programmable Timer question

Discussion in 'General Electronics Discussion' started by kong, Jun 5, 2013.

  1. kong

    kong

    122
    2
    Sep 26, 2010
    So I got a couple of these to mess around with the other day and from my understanding from looking at the data sheet I can see that it is a ripple counter with 24 stages....my question is that can it be wired just like you'd wire a 4060 counter?

    What about the extra binary inputs and other pins? It seems slightly different and I don't know how to wire it up. I also don't know what pins I can leave out and what modes it can be configured to, etc. Anybody who could shed some light would be greatly appreciated.

    Thanks,
    G
     
  2. duke37

    duke37

    5,213
    718
    Jan 9, 2011
    Looking at the data, the binary inputs are to set the division ratio.
     
  3. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,266
    Nov 28, 2011
    Read the functional description in the data sheet. If you don't understand some of the terminology, Google it. Re-read it as necessary until you understand it. Also, get data sheets from other manufacturers. Some may have better explanations than others.
     
  4. kong

    kong

    122
    2
    Sep 26, 2010
    So I found a suitable datasheet and it turns out this is a really neat chip. I wanted to try dividing down a watch crystal (32768hz). The 4536 has 24 divider stages. I fed 32hz into IN1 as a test and set the binary code select pins so that stage 5 of the divider chain would come out on pin 13, the "decode out" pin. Since 2^5 is 32, I got a 1hz output. I wonder how to calculate the output of the 24th stage with a 32768hz crystal?
     
  5. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
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    Nov 28, 2011
    Every Qn output is half the frequency of the previous one, Q(n-1). With a 32.768 kHz clock, frequencies will be:
    Q1: 16384 Hz
    Q2: 8192 Hz
    Q3: 4096 Hz
    Q4: 2048 Hz
    Q5: 1024 Hz
    Q6: 512 Hz
    Q7: 256 Hz
    Q8: 128 Hz
    Q9: 64 Hz
    Q10: 32 Hz
    Q11: 16 Hz
    Q12: 8 Hz
    Q13: 4 Hz
    Q15: 2 Hz
    Q16: 1 Hz
    Q17: 0.5 Hz (one complete cycle every 2 seconds)
    Q18: 0.25 Hz (" " " 4 ")
    Q19: 0.125 Hz (" " " 8 ")
    Q20: 0.0625 Hz (" " " 16 ")
    Q21: 0.03125 Hz (" " " 32 ")
    Q22: 0.015625 Hz (" " " 64 ")
    Q23: 0.0.0078125 Hz (" " " 128 ")
    Q24: 0.00390625 Hz (one complete cycle every 256 seconds).
     
  6. kong

    kong

    122
    2
    Sep 26, 2010
    Ah, that is good to have so I can check my math. I think I got it right.

    The initial frequency(32768hz) divided by the number of divider stages, 2^24, or 16777216. I got about 0.20. So then I did 1/0.20 and got 5. 5 being 5 minutes, or roughly 5 minutes. So Q24 will go high about once every 5 minutes.
     
  7. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,266
    Nov 28, 2011
    Right. 256 seconds is 4 minutes and 16 seconds. That's the total cycle duration at Q24. So from reset, Q24 will be low and will remain low for 2 minutes and 8 seconds, then it will go high for 2 minutes and 8 seconds, then it will return low and the cycle will repeat.
     
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