Eugenio Mendez

9S08QG8 CLOCK AGAIN

Discussion created by Eugenio Mendez on Jan 11, 2008
Latest reply on Jan 12, 2008 by bigmac
Hi
I'm testing the 9S08QG8
If I use a external crystal and generate a square wave I get a perfect wave.
 
for(;:smileywink: {
 PTBD_PTBD2=1;        //bset
_asm NOP
PTBD_PTBD2=0;       //bclr
 _asm NOP
__RESET_WATCHDOG();  // feeds the dog
}
 
 
But when I try to generate the same square wave with the internal clock the period have a
variation of 20 to 30 %.
I note that because using a digital osciloscope (TEK 210) is not easy to syncronize the wave.
You see successive periods increasing and decreasing its size
May be this variations are normal using the internal clock.
If I understood the trim procedure  if for to achieve  an exactly frecuency but not for to achieve stability
 
 
Someone made this experience?
For example Someone could comunicarce with SCI using the internal oscillator?
Best Regards
Eugenio
 

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