testing an oscillator and other electronic devices on a circuit board . one method of the present invention comprises powering the oscillator . providing test instructions to a microprocessor on the circuit board to place the microprocessor in a test mode . receiving a clock signal from the oscillator at a multiplexer in a field programmable gate array . receiving operating instructions at the multiplexer from the microprocessor . multiplexing the clock signal to an external access port with the multiplexer in response to the operating instructions and measuring the frequency of the clock signal at the external access port .