BCD Clock

Use military 24-hour time, running from 00:00 to 23:59.

Others have already jumped on my fix (military time), so I'll suggest the hard way. Use a gate to detect 13 hours and do a parallel load of '1'. You will need a counter with a parallel load (direct set, or some such thing). I better way would be to detect twelve and use a counter with an enable (detect 59 minutes) and a synchronous load.

You might have a reason to be using logic chips, but look into what microcontrollers can do for you. You can implement a very feature-rich clock using a micro, and change it any time and any way you want. To accomplish the same feature-richness with logic chips would be nearly impossible. The only other alternative, and one which you should also consider if this is more of an academic exercise, is to use a CPLD or FPGA. Then you can develop logic design skills instead of software skills, while avoiding the limitations of discrete logic chips.

Good day!

You must reload the hours counter with 01 instead to reset the counter to fix, You must switch to a presettable counter if you are not using it a suitable part can be the CD4029 chip or 7416x ( x = 1,2,3,4) or similar part

in alternative you can count like in Italy

00:00 again for half day

and so on

and eventually add 1 ( one ) to hour digit before display

"demo" ...

Are you a technical person? This is the change to amaze your friends!

Just do the right thing and rollover to 00:00:00 after 23:59:59. And also display a (sortable) date format like 2005-07-23.

;-) Arie de Muynck

There must be a solution at .

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thanks

The BCD clock at:

Works like this:

You get a falling edge at pin 1 of the hours counter which advances the counter to 13 hours. This produces a high level at pins 2 and 14 which resets the counter to 0.

So you have that much working.

The reset signal stays high for a few milliseconds determined by the RC at pin 11 of the inverter. Pin 12 of the next inverter will move high a short time after pin 10 moves low, which applies a high level to pin 1 (clock input) of the counter. When pin 10 moves back high, pin 12 will move low a short time later applying a falling edge to the counter which advances it from zero to 1. So, it's now 1:00 PM instead of 0:00 PM.

Should work with the right parts.

-Bill

The power went off today and the 'goofy clock' was happily reading out the 'fail' time and date, restore time and date, also for the last 2 power failures. It stores 8 events. This is a microcontroller based device with maybe 1200 lines of assembly code. I also have a triple display version to do multiple time zones with 12/24 hour mode selectable for each zone. Are you doing a BCD clock as some sort of exercise to show it can be done? To prove a point? A class assignment? Dammit, I can do it?

Chris Carlen is right about the feature rich possibilities of the microcontroller world. Next software revision of goofy will include a WWVB receiver from Galleon.

I used to prefer hardware versions because they seemed simpler but the flexibility of microcontrollers is so great that I only use the hardware for things too fast for the controller, even then with PLDs, CPLDs, etc. A long time ago a friend pointed out that the only difference between hardware logic and the computer is the sequential nature and temporary storage of intermediate results. Reprogramming beats the the hell out of trace cuts.

GG

Always make NEW mistakes.