What is the mechine cycle for the pic 16F877a ?

[thannara123]

How to i find the mechine cycle for the PIC16f877a ?
And how to find other micro controler mechine cycle ?

 

[paulfjujo]

1 cycle =1000000 / [ 4/FOSC(in MHz)] in µS
FOSC can be internal (inside the PIC) or external , use of a Quartz or an external clock device generator.


for Other PIC18F you can active a PLL multiplicator => FOSC*4 => 1 cycle= 1000000/ FOSC µS

for executime time
Code operation take mainly 1 cycle ( it's explain why we divide FOSC/4)
but some of them can take more than 1 cycle
exemple Goto adresse => 2 cycles
Test true => 2 cycle ,because of jump.
and special math op like Multiply 8x8 take many cycles.

 

[thannara123]

I meant the the machine cycle ? that is how much cycles are needed for execute single instruction .
for example, 12 cycles are needed for execute one instruction in 8051

 

[Allen6502]

If the 8051 needs 12 xtal clock cycles then the 877A would need 4 xtal clock cycles for one instruction.

Read Pages 73-74 of "Mid-range MCU Ref.pdf" doc DS00097D

Allen