4536 Programmable Timer question

[kong]

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

 

[duke37]

Looking at the data, the binary inputs are to set the division ratio.

 

[KrisBlueNZ]

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.

 

[kong]

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?

 

[KrisBlueNZ]

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).

 

[kong]

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.

 

[KrisBlueNZ]

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.