Compass 5 Click is based on the AK09918C, a 3-axis electronic compass with high sensitive Hall sensor technology from AKM Semiconductor. This I2C configurable electronic compass incorporates magnetic sensors for detecting terrestrial magnetism in the X, Y, and Z-axis. It has built-in ADC with 16-bit output data for each 3-axis magnetic component, a built-in magnetic sensitivity adjustment circuit and overflow monitor function, and several operating modes with a typical sensitivity of 0.15µT/LSB. It also has the limitation for the measurement range that the sum of absolute values of each axis should be smaller than 4912 μT. When the magnetic field exceeded this limitation, data stored at measurement data are not correct, which is called Magnetic Sensor Overflow.

This Click board™ includes a low-noise LDO voltage regulator SPX3819 from MaxLinear to provide the 1.8V supply voltage for the AK09918C and possesses several operating modes: Power-Down, Single Measurement, Continuous Measurement, and Self-Test Mode. When power is turned ON, an AK09918C is in a Power-Down Mode. When a specified value is set in a MODE register, the AK09918C transits to the specified mode and starts operation. When a user wants to change Operation Mode, transit to Power-Down mode first and then transit to other Modes. After Power-Down Mode is set, a period of at least 100μs is needed before setting another Mode is possible.

Compass 5 Click communicates with MCU using the standard I2C 2-Wire interface with a frequency up to 100kHz in the Standard Mode, and up to 400kHz in the Fast Mode. Since the sensor is supplied with 1.8V logic voltage level only, also featured on this Click board™ is a PCA9306 voltage-level translator from Texas Instruments. The I2C interface bus lines are routed to the dual bidirectional voltage-level translator that allows this Click board™ to be interfaced with both 3.3V and 5V MCUs.

This Click board™ is designed to be operated with both 3.3V and 5V logic voltage levels that can be selected via VCC SEL jumper. This allows for both 3.3V and 5V capable MCUs to use the I2C communication lines properly. However, the Click board™ comes equipped with a library that contains easy to use functions and an example code that can be used as a reference for further development.