Xtrinsic eCompass sensor fusion software from Freescale Semiconductor, Austin, TX, works with the company's Xtrinsic accelerometer and magnetometer devices to provide fully tilt-compensated and calibrated electronic compass data. The software features roll, pitch, and compass angles; a 4-element model is available that supports hard iron calibration; a 7-element model supports both hard-iron and soft-iron interference correction; standard ANSI C source code; a 20 KB compiled code size; 6.5 KB RAM requirement; and a sensor simulation module for immediate verification.