A complete CMOS integrated microsystem for detecting the direction of the Earth's magnetic field (whose full-scale value is on the order of 60muT), realized with the micromodule approach, including both sensor and electronic interface circuit, achieves 4deg accuracy on the measured angle and provides a digital output. The system response is linear in the range of plusmn60muT with a maximum non-linearity error of about 3% of full-scale.