# Block diagram for a 24 hour clock

Discussion in 'Homework Help' started by Banjo 3100, Mar 21, 2012.

1. ### Banjo 3100 Thread Starter New Member

Mar 21, 2012
2
0
I need to design a block diagram for my 24 hour clock but I was never good at designing them My circuit schematic is uploaded and my attempt at the diagram is as follows:

Crystal oscillator --> Counter --> Decoder --> 7 segment display (with a feeder called debounce switch going tinto the counter)

If anyone could help I would be very grateful, thanks

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2. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
Welcome to AAC!

Not quite what you asked for, but close.

Yet another take, complete with crystal oscillator...

Digital clocks

3. ### Banjo 3100 Thread Starter New Member

Mar 21, 2012
2
0
Thanks However I have just done a quick sketch of what I think it the block diagram would be. I am debating about whether reset would be a 6th subsystem, because it can be tested, so some elucidation would be appreciated http://tinypic.com/view.php?pic=izxov9&s=5

4. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
Something you might think about, AAC has a local system of attachments and albums. If you followed my links you will have seen examples of both.

There isn't any mystery about drawing, and pencil is OK. In my view reset is a subsystem of the control circuitry, which I drew on the digital clock thread. The digital clock has a different block diagram, I wonder if you even looked at it.

I tried using the img link on your site, it was way too big at 1598 pixels. Using M/S Paint, which is also what I use for my drawing, I brought this down to 800 pixels wide.

If you look you will note some differences how we approached our drawings. You did not segregate the systems very well, think of signal flow going from left to right or top to bottom (as you have done), but separate them. It is, after all, a block diagram. Each system is a block. Your diagram resembles a flow chart, but you still have not delineated each section very well.

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Last edited: Mar 21, 2012
5. ### bethesdakid New Member

Apr 4, 2012
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is there a chip with an output every 24 hrs?

6. ### panic mode Senior Member

Oct 10, 2011
1,328
305
there are RTC chips that provide stable clock output (such as 1Hz) but i don't think any of them would do 24h. you can add counter(s) to get any period you like but why not use MCU for this? this is exactly kind of job programable chips are good for.

7. ### b_gravedigger New Member

May 12, 2009
6
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The DS3234 RTC can give you an interrupt evey time the hours, minutes and seconds in it's clock match the predefined values you select.
So, if you do not mess with the clock in the meantime, it should give you the interrupt every 24 hours.