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Ronald Dekker put together an LED clock using a PIC 16F84 microcontroller. Some people would wonder why a $5.00 clock from the store couldn’t be used. It could be, but where would the fun be in that?
“The 16F84 processor used here is a little bit out dated and no longer in production. I used it because of the simple fact that I had it lying around. The more modern 16F628 is pin compatible and will perform equally well. The 16F84 has too few I/Os to address all the anode and cathode drivers directly (Fig. 3). A 74HC563 8 bits latch was used to extend the number of outputs by another 8 bits at the expense of a latch enable signal taken from port A. The eight outputs from the latch, together with the lowest 4 bits of port B from the PIC drive address the cathode drivers. Since only one of the anode rows is switched on at any given moment, a HEF4028 1-of-10 decoder could be used to activate one of the six rows using only 3 bits (A0…A2). These bits are connected to the higher 4 bits of port B. To prevent unwanted illumination of LEDs during the multiplexing of data to the 74HC563, I/O bit A3 from port A is used to completely disable all the anode drivers. ”
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August 24th, 2007
silicon cementery
August 24th, 2007
cool
September 3rd, 2007
Nice!
It’s possible get the circuit squematic, list of components and of course the program’s PIC?
i wanna do this project! it’s very nice stuff!
September 4th, 2007
Click on the link in the article, looks like code and circuit are provided.
November 19th, 2007
nice! can this be modified on 60hz ac mains? thanks!
September 5th, 2008
hi
i need colok circuit,plz help me
tank you
May 9th, 2009
hi. can you explain how to make this clock?
May 9th, 2009
i need this clock circuit. what program it has? please answer me?