I found that probably the best approach is to let timer1 do the 2s interrupts and use another timer or timer1 reg polling method to do the 1s. When the 2s timer1 occurs just synchronize the other timer or if it was a polling method then nothing else have to do really. Tamas On Thu, May 22, 2008 at 7:58 AM, Electron wrote: > At 03.45 2008.05.22, you wrote: > >On Wed, May 21, 2008 at 7:40 PM, Rolf wrote: > >> Mark Rages wrote: > >>> On Wed, May 21, 2008 at 6:48 PM, Rolf wrote: > >>> > >>>> The simplest thing is to set the most significant bit of the TMR1H > byte > >>>> very soon after the TMR1 interrupt.... (to be absolutely safe, it must > >>>> be within 256 ticks of TMR1 or 7.8ms). > >>>> > >>>> bsf TMR1H,7 > >>>> > >>>> What this does is cause the interrupt to happen in exactly 1 time per > >>>> second .... ;-) > >>>> > >>> > >>> Good idea (update only the high byte, let the low one run) but it > >won't work. > >>> > >>> >From the datasheet: > >>> > >>> The Timer1 high byte is updated with the contents of TMR1H when a > >>> write occurs to TMR1L. > >>> > >>> Regards, > >>> Mark > >>> markrages@gamil > >>> > >> > >> Hmmm... I took that from the Mid-Range family 'datasheet'..... pg 12-12 > >> > >> > > > > > >Actually, I was quoting a random 18F datasheet that Spotlight brought > >up on my laptop. > > > >I think there must be a difference between mid-range (which you were > >referencing) and 18F (which I was referencing) parts. But the 30F5011 > >that Mario is using is different still. It is a 16-bit part and > >doesn't need the high/low synchronization hack. So your idea will > >work: Mario can just "bset TMR1,15" in the timer1 ISR. > > But what is the PR1 register for, then? > > Regards, > SuperMarioBros > > > > > >Regards, > >Mark > >markrages@gmail > > > >-- > >Mark Rages, Engineer > >Midwest Telecine LLC > >markrages@midwesttelecine.com > >-- > >http://www.piclist.com PIC/SX FAQ & list archive > >View/change your membership options at > >http://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- Rudonix DoubleSaver http://www.rudonix.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist