Frequency Generation of 32.768hz

I am very new to the Arduino and would appreciate some help or direction.

I would like to use an output to supply a frequency of 32.768khz. It would be great if there are internal clock settings that I could use to set this frequency up and then send out on one of the pins.

Is there any documentation available for the Arduino that talks about the internal clocks?

Thanks

TimV

Go to atmel's website and download the ATmega168 datasheet. If you want to know what you can do with your Arduino's microcontroller, go to the source for your documentation.

http://www.atmel.com/dyn/products/product_card.asp?PN=ATmega168

  • Ben

Are you sure you mean 32.768Hz and not 32.768KHz, there is a difference, one is possible and the other is not using the 16MHz clock of the Arduino.

Thanks Ben:

I have not seen that document so I have some reading to do now :)

Tim

Hi Grumpy_Mike:

I did mean 32.768Khz and not just hz. Hopefully this is the one it can do with internal timers. I changed my original post so that anyone following will read what I really wanted to ask.

Tim

I think the closest you'll be able to get using a 16 MHz clock is 32.7869 kHz, which is around 0.06% off of your desired frequency.

  • Ben

Thanks Ben

Tim

I did mean 32.768Khz and not just hz.

If you mean 32768Khz then would be something like 32768000 hz. I guess you cannot get 32768000Hz from a microprocessor running at 16Mhz. I guess you really meant 32768Hz.

I did mean 32.768Khz and not just hz.

If you mean 32768Khz then would be something like 32768000 hz. I guess you cannot get 32768000Hz from a microprocessor running at 16Mhz. I guess you really meant 32768Hz.

This is a real pain in the rear that happens between USA syntax and European syntax. You see, in the US we use . to mean a fraction of a number whereas in Europe you use ,

We use , to seperate groups of thousand powers where as you use .

So you see, it's totally backwards. When we mean 32768Hz we write 32.768KHz and you would write 32,768Khz

This is REALLY annoying. It's hard to know what people mean when you can't count on the same syntax.

But since we in the US are ALWAYS right you should just get used to it! ;-) (I'm ducking now and heading for the exit!)

Would be better to write just the number without decimal places if we are talking about integer numbers.

I wrote about 32768Hz because that is a usual frequency used in microcontrolles when lower speeds and better battery life are needed.

Would be better to write just the number without decimal places if we are talking about integer numbers.

Yes, you are correct. Not using any seperators would be best if the # is an integer. Then there is no confusing between how US people write things and how the rest of the world does.

I am sorry to have caused all this confusion. :slight_smile: I meant thirty two thousand seven hundred and sixty eight hertz. It would have helped if I had stated that I wanted to use the frequency as a clock base. I was thinking that I could use a pin on the Arduino instead of a clock crystal to drive a Maxim DS1306 rtc.

I stopped at my favourite electronics store tonight and picked up an actual clock crystal.

I often wonder what other differences there are that we should be aware of. I got caught helping someone on a forum in England in that he was asking a wiring question. I of course referred to gnd instead of wiring to earth so I felt pretty foolish on that one.

Thanks for the input

Tim

I often wonder what other differences there are that we should be aware of. I got caught helping someone on a forum in England in that he was asking a wiring question. I of course referred to gnd instead of wiring to earth so I felt pretty foolish on that one.

I read an interesting thread on the piclist a number of years ago.

If you have a dangerous industrial machine, in the US you will use green to indicate it is safe (ie stopped), and red to indicate it is dangerous (ie running).

In Europe, you would use red to indicate it is stopped (ie safe) and green to indicate it is running (ie dangerous).

The systems are exact opposites, both make perfect sense, and it could be a matter of life or death to get it right.

Yeah, it would be nice if we could just all agree on a single standard. Of course, neither party is going to want to be the one to concede defeat.

I often wonder what other differences there are that we should be aware of. I got caught helping someone on a forum in England in that he was asking a wiring question. I of course referred to gnd instead of wiring to earth so I felt pretty foolish on that one.

I read an interesting thread on the piclist a number of years ago.

If you have a dangerous industrial machine, in the US you will use green to indicate it is safe (ie stopped), and red to indicate it is dangerous (ie running).

In Europe, you would use red to indicate it is stopped (ie safe) and green to indicate it is running (ie dangerous).

The systems are exact opposites, both make perfect sense, and it could be a matter of life or death to get it right.

single standard I seem to remember that in 1885, how I remember is that its the same year Cheers was opened, there was a bill in the US house along the lines that 'we're going full steam ahead with the metric system'. But as it turns out all those billionaire industrialists decided they couldn't afford the retooling costs, a couple of brown paper bags changed hands, and the bill died. ... Which is why you still have to buy 11/72" spanners... :)