A digital adjustable chip oscillator comprises a voltage control oscillator, a reference voltage circuit, a voltage regulation circuit, a digital tuning circuit, a frequency detector and a programmable controller. The oscillator generates an oscillation signal and receives a control voltage and an operating voltage from the voltage regulation circuit and the reference voltage circuit to stabilize and adjust the frequency of oscillation signal. The digital tuning circuit receives a digital code stored in a programmable memory to adjust the control voltage. The frequency detector detects and compares the frequency of oscillation signal with a first and second frequency, wherein when the frequency of the oscillation signal lies between the first and second frequency, the frequency detector outputs a high voltage signal and otherwise the frequency detector outputs a low voltage signal. The programmable controller receives the high voltage signal to stop a programmable counter to acquire the digital code.