On Tue, 10 Nov 2009 10:05:06 -0800, "Vasile Surducan"
<piclist9@gmail.com> said:
> BTW,
> assuming you want to build it from scratch, how many IO pins will be
> necessary for a
> 7 seg clock displaying:
> dd:mm:yyyy     hh:mm:ss:tt   totaly16 digit
> where the format displayed is day:month:year 
> hour:minute:second:milisecond

Only one pin if you use extra parts :) But if you want to directly drive
the display, and also choose a "standard" display you will have 8
segments plus as many digit commons as you have digits. So if you really
need milliseconds, that sounds like 9 digits and that would total 17
pins. Charlieplexing would use 10 pins but it's not as bright because
the duty cycle is smaller.

Cheerful regards,

Bob

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