Proper Interrupt mode Selection in MCU

[mohammadyou]

if we want to detect both edge signals as a interrupt (for example we have a pulse wave signal ) which one of these method are more appropriate :
1) set the micro for Any Logical Change
2) set as falling edge and after interning to the Interrupt mode toggle the register and set it to rising edge mode.


Another problem that I have been dealing with is, using higher external crystal and divide it to the some low frequencies, does give us more precise clock than we use the crystal with the small value ?

Thanks

 

[babar_ali]

set as falling edge and after interning to the Interrupt mode toggle the register and set it to rising edge mode

You have not mentioned about the microcontroller. The best can be achieved using capture module of the microcontroller...

 

[123jack]

If your microcontroler can do the change for you (your option 1) that will be easier for you and more efficient.
If it doesn't you will have to do it yourself (your option 2)
And no - reducing a higher frequency clock rate will not give you a more precise clock.
(Unless you are working under very strange conditions)

 

[mohammadyou]

Cheer mates
my mcu is avr and there is an option for any change.
123jack would you please give some information about the condition you have talked about.

 

[123jack]

hi mohammadyou
by very strange I mean very unusual such as extreme precision using very cheap components or perhaps
extreme noisy environments with poor quality equipment etc. Not something you would normally encounter.
The comment was off the cuff really - sorry if it confused you.

 

[mohammadyou]

Thanks 123jack