What problem do you have if you tilt it? What output do you expect? If you have a 3 axis magnetometer, you can calculate the facing direction even if the device is tilted
#define M_X_MIN -421#define M_Y_MIN -639#define M_Z_MIN -238#define M_X_MAX 424#define M_Y_MAX 295#define M_Z_MAX 472
Which sensor module are you using? The way the different values are transformed depends on the placement of the components on the PCB, so this fact is relevant.What values do you get and what would have been the expected values?
the value that i expected is when i tilt the board, the compass heading degree is not change, i have use tilt compensation algorithm for magnetometer, but still not works, the heading degree still change when i tilt the board..