I confirm what Michael says, in one 16f873-04/P with an external crystal = of 40Khz in the TMR1, the oscillator does not become stable instantaneously, at least delays 1 = second, in my program I had to make it ignited constant with bsf T1CON,T1OSC and = enable/disable the TMR1 with bsf/bcf TICON,TMR1ON. This matter madman turned me, until the oscillator happened to me to be = made ignited constant since the datasheets do not say the time there becomes stable the = oscillator, which according to my tests is more than 1 second. Regards N=E9stor A. Marchesini Chajari-Entre Rios-Argentina ICQ # 50983752 colo MSN nestorm_des@hotmail.com nestorm@xinet.com.ar nestorm@deselectronica.com.ar michael brown escribi=F3: > Rikard Bosnjakovic wrote: > = >> On 4/20/07, Richard Seriani, Sr. wrote: >> >> = >>> I'm new to PICs, but maybe the information in Table 17-4 of the >>> datasheet, particularly parameter 32 (oscillation start-up timer >>> period) will help? >>> = >> Except for the confusing datasheet (it's sometimes referring its >> internal oscillator as external, and you have no idea which is which), >> I think this table will help. According to it - and if I parse it >> correctly - it's around 30 usecs. And since the timer won't start >> before the user presses a button, it's perfectly in limits. I mean, >> noone will be able to turn the device on and within 30 usecs press the >> button. >> = > > It can take a second or two for the oscillator to come all the way up, = > but it's not like you're going to damage the PIC if you enable the = > counter early. I think they just want you to be aware that you can't = > just turn it on and expect it to instantly snap into action counting = > time accurately. The T1OSC consumes very little current, you could = > probably just let it run all the time even when sleeping if you need to = > be able to measure time as soon as you wake up. > > Yeah, the datasheet is pretty confusing about INTOSC vs INTRC etc. In = > fact they are downright ambiguous about it and admit so as a disclaimer = > in some datasheets I've seen. The two-speed startu, failsafe and = > associated speed switching are also somewhat confusing, but you will = > figure it out as you go along. You don't have to really concern = > yourself with all the failsafe stuff right now. T1OSC is completely = > seperate from INTOSC/INTRC. They can be turned on and off = > independantly. TMR1 won't count until you enable it, regardless of = > T1OSC running. = > > = -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist