Driver for an Asahi Kasei AK8975 electronic compass.
All correct at time of writing, but as always, manufacturers love to move things around on their website.
http://www.asahi-kasei.co.jp/akm/en/product/ak8975b/ak8975b.html
http://nexp.tistory.com/attachment/cfile10.uf@20418A044C7330720F6435.pdf
This code has been tested using an InvenSense MPU-6050 evaluation board with the MPU-6050 in bypass mode to attach the auxiliary I2C bus to the primary I2C bus.
http://invensense.com/mems/gyro/documents/AN-MPU-6000EVB-00_v1.0.pdf
The MPU-6050 evaluation board was attached to a SolderCore:
Although the AK8975 supports SPI mode, we have no way to test this and consequently do not offer an SPI initialization function.
| Parameter | Supported settings |
| Range (µT) | ±1300 |
| Communication | up to 400 kHz (I2C) and 3 MHz (SPI) |
| Macros | |
| AK8975_I2C_ADDR | AK8975 8-bit I2C address selected by CAD1:0 |
| Functions | |
| ak8975_initialize_i2c | Initialize sensor on I2C bus |
| ak8975_initialize_transport | Initialize sensor on a transport |