1hz clock

[mattcf]

an ATtiny and an external 8 or 16 Mhz crystal could do it (Set it up to pulse every second)

[baum]

I am going to end this topic and start a new, more specific one. Thanks for all the help!

[CrossRoads]

Yes,
Feed 64 KHz into CCLK, RCO from stage 1 into stage 2, RCO Pulse from will yield a low going pulse 1/64K wide 1x a second.

http://www.eetkorea.com/ARTICLES/2001SEP/2001SEP06_AMD_AN.PDF
See figure 3 for suggestion on getting 64KHz source. Other ways also possible, this seems pretty straight forward.
http://www.z80.info/uexosc.htm

[baum]

seems pretty straight forward.

Not as easy as I would have hoped, but I guess it will be fine. For the first link, they don't specify where the output is...any ideas?

Also, is there a way I can get 50% duty cycle?

[CrossRoads]

Enable the outputs, and use the MSB, which will change hi/lo/hi/lo every 1/2 second.

[baum]

right...

how exactly do I setup the crystal though?

[baum]

I want to connect the 65.536kHz crystal to the clock of a binary counter. no microcontrollers involved.
Thanks!

[CrossRoads]

Reply #24 has circuits to make the 64K oscillator that will drive the clock line.

[baum]

But which would should I use? There are three on that page.

[baum]

My counter chip is a 74393, i will be running the power supply at 3V (2x AA) and I will be using this crystal.

[baum]

Whoops. Then how about 3x AA, which would be 4.5V?

[baum]

Whops again.... I meant to say 74HC393. Sorry for the confusion!

[CrossRoads]

Try the simplest one first baum, if that works then you're all set.
If not, try another.

[baum]

So the second one w/ 3 inverters and a 100N cap?

[CrossRoads]

I would have suggested Figure 3 from this link first
http://www.eetkorea.com/ARTICLES/2001SEP/2001SEP06_AMD_AN.PDF
1 inverter, couple of 22pF caps, couple of resistors.