Digital clock design questions?

Spragmatic

I am building a large digital clock to hang on my wall. Using a SX28 protoboard to control. I understand all of the wiring and such, but not quite sure on how to write a simple code for function. I'm building (4) large seven segment displays with 2 dots for the seconds. I would like to be able to set the seconds and hours separate if possible. Also would like the (2) seconds dots to flash. Can I just use the SX28 for real time or should I use a DS1307 board? Thanks for any help! Greg

Zoot

With an accurate chip clock source (e.g. TTL oscillator) the SX should be fine for regular time-keeping IF you don't mind resetting the time/date when the power goes off. Otherwise, an external RTC like a DS1302 or DS1307 will preserve the time in a power outage.

There are formulas for calculating day of the week, etc., as well from the time and date, so these functions can be handled w/o an external RTC as well.

e.g. Dr. Allen's code here: http://forums.parallax.com/showthread.php?p=868461

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Spragmatic

Thanks for the info!