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8051 out put pin frequency

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hello, i am using atmel 8051 with 11.0592 mhz crystal.
what will be the frequency when i make a pin high- low;

P1.0 = 1 ;
p1.0 = 0 ;

what will the frequency of p1.0 pin?
 

getavinks@gmail.com said:
hello, i am using atmel 8051 with 11.0592 mhz crystal.
what will be the frequency when i make a pin high- low;

P1.0 = 1 ;
p1.0 = 0 ;

what will the frequency of p1.0 pin?
Click to expand...

If you used 12MHz crystal the max frequency would be around 500kHz, with 11MHz it will be roughly 11/12 of that estimation ..
:wink:
IanP
 
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IanP said:
If you used 12MHz crystal the max frequency would be around 500kHz, with 11MHz it will be roughly 11/12 of that estimation ..
:wink:
IanP
Click to expand...


Thanks for your response.

How to calculate this frequency?
 

getavinks@gmail.com said:
Thanks for your response.

How to calculate this frequency?
Click to expand...

The original 8051 core runs at 12 clock cycles per machine cycle, with most instructions executing in one or two machine cycles.
So, one machine cycle takes 1 micro-sec if the 8051 is operating from a 12 MHz clock.
SET and CLR istructions are executed in one machine cycle.

1us+1us=2us ====> f=500kHz

:wink:
IanP
 
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Execution time

The time needed to execute any particular instruction is determined by the formula
instruction_time.png


T is equal to C times 12 divides F

C is the number of cycles to execute the program

F is the frequency of the crystal
 
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see 8051 has a DIVIDE by 12 circuit built inside. So first of all divid ur clk freq by 12 and then inverse gives execution time for each cycle.

12MHz/12 = 1MHz

Execution time = 1/1MHz = 1uS

so it will take 1uS for setting bit and then 1uS for reset bit

Hence 2uS

Hence frq = 1/2uS = 500kHz


HOPE IT HELPED !!!
 
Thanks it was help full
:pH said:
see 8051 has a DIVIDE by 12 circuit built inside. So first of all divid ur clk freq by 12 and then inverse gives execution time for each cycle.

12MHz/12 = 1MHz

Execution time = 1/1MHz = 1uS

so it will take 1uS for setting bit and then 1uS for reset bit

Hence 2uS

Hence frq = 1/2uS = 500kHz


HOPE IT HELPED !!!
Click to expand...
 

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