Help with digital clock...

[eehelp]

I have to build a digital clock using 74161 counters for my final project, but I'm having troubles. I got part of the seconds to work, but I'm stuck when it comes to the rest of the seconds, minutes, and hours. Here's the schematic of what I have now: http://www.flickr.com/photos/38401311@N05/4541585238/. Thanks in advance!

[retched]

Bill_marsden has a clock diagram you will want to look at. Search the forum for clock circuits and you will find plenty.

Ive found the diagram:

[eehelp]

I've been looking all over for some examples, but I can't find any. I have to use 74161's for this project unfortunately.

[kingdano]

the posted diagram, looks to me at least, like an overall architecture that you can use with any device essentially.

what it is showing you is an overall topology to apply to your specific devices.

i think.

[beenthere]

Use "74161" as a search term in Google to get a data sheet. That should answer some questions - like how to get the tens part of the seconds counter to go. Onece you have that, everything else should fall into place.

[eehelp]

I looked at the datasheet, but it doesn't really say anything about how to make different counting sequences...

[rjenkins]

If I remember correctly, the 161 is a synchronous counter with load.

To do seconds, minutes & hours you would need two stages each.

With each two decade section, you have to use a few gates to give a signal at maximum count (eg. 59) and use that to activate the Load input.

The next clock pulse would then load the value from the input pins (which you set to fixed levels) rather than incrementing the count, so 59 -> 00 or 12 -> 01. (Or 23 -> 00 if you prefer).

If you are on to counters you should understand simple gates, so start drawing you circuit!


ps You have already said it's homework, so no one will design it for you - clues and pointers only.

[eehelp]

Thanks for the advice, but I just really don't understand how to make this work. Could anyone give me more specific advice? I switched my major a while ago, so now I just have to pass this class...

[retched]

http://www.kpsec.freeuk.com/counting.htm

This should help a little.

[eehelp]

Thanks for the link, it did help with resetting the counter so it only counts to 5. So now for some reason the 2nd counter for the seconds is starting to increment when the first counter gets to 8, instead of 9. Here's what my circuit looks like: http://www.flickr.com/photos/38401311@N05/4553827050/