Patent ID: 7400130

Claim:
An integrated circuit device comprising internally on-chip: an oscillator with a signal output, a reference clock input, a first counter with a count input, a control input and a counter output, a second counter with a count input, a control input and an overflow indication output, and a test control logic circuit; wherein the count input of the first counter is connected to the signal output of the oscillator, the count input of the second counter is connected to the reference clock input, the overflow indication output of the second counter is connected to an input of the test control logic circuit, the test control circuit has an output connected to the control input of the first counter to apply a stop counting control signal to the first counter after it has received an overflow indication signal from the second counter; and the first counter after it has received a stop counting control signal provides a count at the counter output which is indicative of the output frequency of the oscillator.