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[brownr72]

I am new to the forum here...I want to build a simple digital circuit that does the following.

It has two outputs, CLOCK and LATCH.

- the CLOCK output is a clock signal (a square wave) at about 1 MHz
- the LATCH is zero most of the time, but every N clock cycles (where N is around 81 or 82) it briefly goes to 1

I'm not sure yet which edge of the clock (pos or neg) should trigger the LATCH, but I assume that is a trivial detail.

I know that these things called "counter chips" exist. I was wondering if someone could point me to a useful one. Since N is 81 or 82, it's going to need at least 7 bits. My circuit needs to know when it has reached the final count. I also need some kind of oscillator to produce the clock signal.

Thanks.

[Iniyila]

brownr72, on 29 November 2010 - 11:38 AM, said:

I am new to the forum here...I want to build a simple digital circuit that does the following.

It has two outputs, CLOCK and LATCH.

- the CLOCK output is a clock signal (a square wave) at about 1 MHz
- the LATCH is zero most of the time, but every N clock cycles (where N is around 81 or 82) it briefly goes to 1

I'm not sure yet which edge of the clock (pos or neg) should trigger the LATCH, but I assume that is a trivial detail.

I know that these things called "counter chips" exist. I was wondering if someone could point me to a useful one. Since N is 81 or 82, it's going to need at least 7 bits. My circuit needs to know when it has reached the final count. I also need some kind of oscillator to produce the clock signal.

Thanks.

you should have a signal generator with 1mhz frequency (you can either use a crystal or a signal generator) and then you can use a SN74LV8154 from texas instruments. it can be use as a single 32bit counter or a double 16bit counter anyway it will do the job. triggering the latch deponds on the latch itself.

building a oscillator with a 1mhz crystal is very easy you can google it and you will find the circuit it (here is a sample : http://how-to.wikia....illator_circuit )