> -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf > Of Rikard Bosnjakovic > Sent: 24 February 2007 05:44 > To: Microcontroller discussion list - Public. > Subject: Re: [PIC] making a quartz clock > > > On 2/23/07, Harold Hallikainen wrote: > > > Yes, Fosc is divided by 4. So, if you have a 4MHz oscillator, > the PIC runs > > at 1,000 instructions per second (some instructions take twice as long, > > like those that modify PC). > > I read about this (and some other crystal-based text) in my PIC-book, > but what I cannot understand is why a 32768Hz-crystal is magical > enough to use for clock-applications. Dividing 32768 with 4 gives me > 8192, and that's a value that I certainly don't connect with anything > that's got to do with timing. you clearly aren't used to thinking in powers of two yet 1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768 65536 devide 32768hz by 2 15 times and you end up with 1hz. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist