How to check the clock frequency using software

Hi,
I have connected 16MHz crystal to micro controller, now I want check this clock speed using software .

i.e I want to verify in which speed micro controller is runnig in case of the crystal is not connected.

I have written small code to check this : I was verifying this on oscilloscope
while(1)
{
delay ();
P1=1;
delay();
P1=0
}

Due to While loop it was difficulty to set the duty cycle .


is there any way to implement this..?

I assume that you connect the crystal as a system clock source, in that case if the crystal malfunctions in any way (broken, disconnected etc)
the system will be frozen, without a system clock no instruction is executed.
The only self calibrating system i have seen is when there is an internal system clock source and a second external clock source is used (an external 32.768Khz crystal) for real time clock,
in that case the small crystal can be used to calibrate the internal clock frequency to a certain accuracy.
The code you have written will output a 1 0 1 0 square wave to P1 but the frequency will be much lower compared to the clock because there are a number of instructions involved which consume time,
the duty cycle should be 50% since the instruction are the same in both states (same delay).

Alex