Dwayne wrote:

>> The accuracy of INTOSC should not matter - you woul=
d use TMR1 as the source
>> for all time critical events.  In other word=
s, TMR1 is running all the
>> time, whether the PIC is asleep or awake.=0D
=


ahaa ... Yes, I was wrong!!
I  forgot that is the clock of Timer1 th=
at "drive" all the timing chain..


>> Why is the PIC awake for a full=
 second?  Does it need to be?
>> A list of the tasks you need to do whil=
e the PIC is awake would help us
>> help you.

 Well, this is my "idea=
l" list of tasks:

- The Rain sensor is an "tipping bucket" type
- Eve=
ry pulse from the rain sensor wake-up the PIC, increment an 8 bit "rain" =
register,  then sleep.
- Every time TMR1 overflow the PIC wake-up and I =
decrement a "countdown" timing register, then sleep again.
- When this r=
egister is down to 0 (30 minutes gone) I take the measures (rainfall and =
temperature).  The value of the "rain" register (8 bit) and temperature (=
16bit) are written on an 24LC256 EEPROM (this is why I need about 1 secon=
d: I haven't said this in the previous mail but I would read also a tempe=
rature sensor as DS1775 digital  Thermometer o similar low cost I2C senso=
r).
- Sleep again (and so on..)
- If a button is pressed (or the EEPROM=
 is full) the logger stops.

  Managements of two interrupts sources (r=
ain sensor and TMR1) seems feasible to me and the 8 pin  are just suffici=
ent...


 regards
 MarcoG




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