How to implement This

[aamir]

I want to build circut with 8051 micro controller  which detects whether Clock signal is available  or not ie I want to detect Clock signal is

presetnt or not how to do this .

[sam_des]

Hello,

You can use one of the timer's counter mode with external trigger. Each transition on clock line will increament the timer count. You can also get frequency/duty cycle of clock signal. Use another timer or simply a soft-delay to time-out detection of clock.

e.g. Get the count in timer before you start your delay. Wait for delay to complete. Check the count again.  You can now decide whether clock signal is present or not.

Be sure to buffer the clock line before feeding to 8051 so that it will not get affected in any way.

regards,
sam_des

[Joe_jj]

Is the frequency of clock signal constant? If yes,only soft delay is enough to solve ur prob.