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[General] Why is Fosc always divided by 4 when before using the prescalar?

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ahmedsaber

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why Fosc always divided by 4 befor using the prescalar ?

hi Everyone

i'm so confused

in general in any MC , always i found that the Fosc divided by 4 before using the prescalar

every equation uses Fosc/4 not Fosc

can anyone help me ?

thanks
 

Re: why Fosc always divided by 4 befor using the prescalar ?

Hi,

in general in any MC...
Click to expand...

not with my MC.

Klaus
 

Re: why Fosc always divided by 4 befor using the prescalar ?

It only PIC behavior. As I call it, toy-oriented mcu.
 

Re: why Fosc always divided by 4 befor using the prescalar ?

ahmedsaber said:
every equation uses Fosc/4 not Fosc
Click to expand...

For the most applications, the clock frequency of the uC's peripherals should be equal or smaller than the CPU clock frequency, otherwise the code would not be able to manage them without risk of losing synchronism. The exact division factor of 4 above is due to the fact that the PIC core, being a RISC processor requires few oscillator clocks to executes instructions, in opposition to other CISC architectures ( e.g 8051 ) whose variants takes either 6 or 12 oscillator cycles .
 
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