Datasheet
Mechanical and Electrical Specifications
20 Freescale Sensor Fusion Library for Kinetis MCUs, Rev. 0.7, 9/2015
Freescale Semiconductor, Inc.
Table 11. Memory Requirements for “All Algorithms” Builds
Freedom Platform Text Data BSS Flash RAM
CodeWarrior
FRDM-KL25Z
96028 72 14776 96100 14848
FRDM-KL26Z
96020 72 14780 96092 14852
FRDM-KL46Z
95956 72 14780 96028 14852
FRDM-K20D50M
88116 72 14972 88188 15044
FRDM-K64F
79724 84 16484 79808 16568
KDS
FRDM-KL25Z
77812 172 14816 77984 14988
FRDM-KL26Z
77828 172 14816 78000 14988
FRDM-KL46Z
77772 172 14816 77944 14988
FRDM-K20D50M
67356 172 15008 67528 15180
FRDM-K64F
65024 184 16652 65208 16836
FRDM-K22F
62268 184 16492 62452 16676
Table 12. CodeWarrior Memory Requirements for FRDM-KL25Z and Single Algorithm
Freedom Platform Text Data BSS Flash RAM
Accel (Tilt) 34280 64 12580 34344 12644
2D Mag 53904 64 12580 53968 12644
Gyro Only 33944 64 12528 34008 12592
Accel/Mag 55172 64 12588 55236 12652
Accel/Gyro 54716 72 12892 54788 12964
9-axis 75552 64 13664 75616 13728
4.7 Magnetic Calibration Metrics
4.7.1 Background
Hard-iron effects are due to magnetic materials in the vicinity of the sensor. These materials result in an
apparent offset to sensor readings when the source of interference is fixed spatially, relative to the
sensor.
For a given point in space, plotting magnetometer measurements at various sensor rotations results in
the sphere shown on the right hand side of Figure 12. This makes sense, as the magnitude of the 3D
magnetic field should not change just because the sensor is rotated.
Soft-iron effects result from the interaction of ferrous materials near the sensor interacting with the
ambient magnetic field. If the source of soft iron interference is again fixed spatially with respect to the
sensor and does not demonstrate magnetic hysteresis, then the sphere of plotted measurements is
distorted into an ellipsoid. This is shown (along with a hard-iron offset) on the left side of Figure 12.
Reference 2: Orientation Representations provides background on the topic of hard- and soft-iron
magnetic compensation. For the case where the sensor and sources of interference are spatially fixed
with respect to one another, the distortions are linear, and can be reversed mathematically. This is the
function of the Freescale magnetic calibration library.