Hi,

The timing of the code (infamed by Myke Predko?) at the end of this mail
simulates to the nearest µsecond using MPLAB.  However, when executed on a
P16F84 using a 4 MHz 3 pin resonator marked
[4.00 (M x], I loose about 1 second every 10 minutes.  Same occurs at
different supply voltages between 3.5 and 6V.

Presumably this is because of the +/-0.5% error (or greater) in the crystal
and my too frequent reliance on 1 microsecond being accurate?

If this magnitude of error is expected for this type of delay code, could
someone please point me to another technique (e.g. TMR0 + prescaler) with
accurate equations which allow accurate pre-calculation of the interval.  

I'm using RA5 hence can't use a 32k crystal for timing.  Is there any other
external timing techniques (sleep or not) for a P16F84?

Is the life of a microcomputer reduced if it is allowed to continuously loop
compared to a sleeping chip?

;
; Delay rountine for P16F84 using 4 MHz crystal.  Sum individual expressions
for total and add
; extra cycles where required
;
MOVLW   0X00?	
MOVWF   COUNT1	
MOVLW   0X00?	
MOVWF   COUNT2	
MOVLW   0X00?	
MOVWF   COUNT3	
MOVLW   0X00?	
MOVWF   COUNT4	
DECFSZ  COUNT4,F  ;2+(3*1)*(COUNT4-1)
GOTO    $-1	
DECFSZ  COUNT3,F  ;2+(3*255+3+2)*(COUNT3-1)
GOTO    $-3	
DECFSZ  COUNT2,F  ;2+(3*255*256+5*255+3+2+2)*(COUNT2-1)
GOTO    $-5	
DECFSZ  COUNT1,F  ;2+(3*255*256*256+5*255*256+7*255+3+2+2+2)*(COUNT1-1)
GOTO    $-7