yamaha MS-3C sensor on samsung galaxy

I have a samsung galaxy s and i have made an application that make a list of sensor in the phone. That program show me many sensor, but my question is on two of them: MS-3C Magnetic sensor -->type:2 MS-3C Orientation sensor -->type:3

why it say that they are two different sensor? in the sheet of yamaha http://www.yamaha.co.jp/english/product/lsi/magnetic_sensor/ it seems to be a single sensor. Why android repor开发者_运维知识库t it as two different sensor? it use the same chip to give me two type of data?

Sorry for my english

Orientation sensor is a virtual sensor that uses the other actual sensors (such as accelerometer and magnetic sensor) to determine orientation. In some cases, that might be done in software. From the link you provided, note this sensor takes an input for an inclination sensor. I guess it is an accelerometer in this case. (What were the other sensors shown on the device? It could be a gyroscope too.) So maybe it has on-chip software or logic to provide the full orientation out from the accel and mag data, or it might just pass through gyro data as the orientation result.