For accurate angle measurement, the two axes amplitudes must be normalized by selecting the proper gain adjustment value in the MAG_GAIN_CONFIG register. The gain adjustment value is a fractional decimal number between 0 and 1. The following steps must be followed to calculate this fractional value:

• Set the device at 32x average mode and rotate the shaft full 360 degree.
• Record the two axes sensor ADC codes for the full 360 degree rotation.
• A normalized plot for the full 360 degree rotations are represented in Figure 8-12 or Figure 8-13.
• Measure the maximum peak-peak ADC code delta for each axis, A_X and A_Y.
• If A_X>A_Y, set the MAG_GAIN_CH register bit to 0b. Calculate the gain adjustment value for X axis:
• If A_X<A_Y, set the MAG_GAIN_CH register bit to 1b. Calculate the gain adjustment value for Y axis:
• The target binary gain setting at the GAIN VALUE register bits are calculated from the equation, G_X or G_Y = GAIN_VALUE_decimal/ 256.

Example 1: If A_X = A_Y = 60,000, the GAIN_VALUE register bits are set at default 0000 0000b.

Example 2: If A_X= 60,000, A_Y = 45,000, the G_X = 45,000/60,000 =0.75. Set MAG_GAIN_CH to 0b and GAIN_VALUE to 1100 0000b.

Example 3: If A_X= 45,000, A_Y = 60,000, the G_X = (60,000/45,000) =1.33. Since G_X >1, the gain adjustment needs to be applied to Y axis with G_Y =1/G_X. Set MAG_GAIN_CH to 1b and GAIN_VALUE to 1100 0000b.