In Reply to: Re: Logic design for setting the time in a 12hr digital clock posted by Russ Kincaid on 12/15/02 at 8:25 PM:
Well, nice way Russ :)
Here's another one:
The counter-Inputs are edge triggert (i don't know if it is low->high or high->low!?), so just insert a EOR gate (for example).
On the A input connect your minute-count-puls and on the B input connect a switch. On every push on the switch the output of the EOR gate is toggled - so is will increase the minute counter.
The same you could do on the hour part.
This makes is simple to change minute and hour directly.
The need to pull up, or push down the level on input B depents if you have inverted or not invertet inputs on your counter.
I hope thats right... shiddy lows and highs ;-)
But note: sometimes the counter will increse on a push - and sometimes it will increse on a release of the shwitch! Depends on the logic level on input A.
Sorry... my english should be terrible *G*