FXTH870xD
Sensors
156
Freescale Semiconductor, Inc.
17.10
Optional Acceleration Sensor Characteristics
17.10.1 Example Z-Axis Acceleration Sensor Calculations (similar for X-Axis)
As an example, consider that the dynamic firmware routine has returned STEP = 6 indicating offset step 6, and A
ZCODE
= 256.
First, refer to lines
to retrieve the step number 6 values for A
ZCODE
= 510 and for A
ZCODE
= 1. Then apply the
following to calculate the sensitivity for offset step 6:
Eqn. 16
Once the sensitivity
A
Z-6
has been calculated, the acceleration A
Z
can be calculated with the following transfer function:
Eqn. 17
Another example where STEP has been returned as 15 and A
ZCODE
has been returned as 256:
Eqn. 18
Then:
Eqn. 19
A
Z-6
A
Z-6
@ A
ZCODE
510
A
Z-6
@ A
ZCODE
1
–
510
=
42.1
42.9
–
–
510
=
0.167g per A
ZCODE
integer
=
A
Z
A
Z-6
A
ZCODE
A
Z-6
@ A
ZCODE
1
A
Z-6
–
+
=
0.167
256
42.9
–
0.167
–
+
=
=
0.3g
–
A
Z-15
A
Z-15
@ A
ZCODE
510
A
Z-15
–
@ A
ZCODE
1
+
510
=
402
315
–
510
=
0.171g per A
ZCODE
integer
=
A
Z
A
Z-15
A
ZCODE
A
Z-15
@ A
ZCODE
1
A
Z-15
–
+
=
0.171
256
315
0.171
–
+
=
=
359g
Summary of Contents for FXTH870 D Series
Page 86: ...FXTH870xD Sensors 84 Freescale Semiconductor Inc Figure 57 Data Flow For Measurements...
Page 171: ...FXTH870xD Sensors Freescale Semiconductor Inc 169 Figure 128 QFN Case Outline...
Page 172: ...FXTH870xD Sensors 170 Freescale Semiconductor Inc Figure 129 QFN Case Outline...
Page 173: ...FXTH870xD Sensors Freescale Semiconductor Inc 171...
