Freescale Semiconductor FXTH87 11 Series, Firmware User Manual

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FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide, Rev. 2.1
18 Freescale Semiconductor, Inc.
Firmware Functions
• Input Parameters:
— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described
in Section 2.3 ). Only the 10-bit uncompensated acceleration result will be updated.
— UINT8 u8Avg: Number of measurements to average into one result. The value can be set to 1,
2, 4, 8, or 16.
— UINT8 u8FiltSelect: If non-zero, 250-Hz filter enabled. Otherwise, 500-Hz filter selected.
— UINT8 u8DynamicOffset: Selects the offset setting for the appropriate acceleration reading.
Default is 6.
.
• Returns :
— UINT8 u8Status: Valid error flags/outputs are described in Table 15 .
Table 14. u8DynamicOffset valid values
Offset Index
Offset when result of function is 256 counts
assuming stand trim.
Span does not change.
0 -70 g
1 -60 g
2 -50 g
3 -40 g
4 -30 g
5 -20 g
6 -10 g
7 0 g (default)
8 10 g
9 20 g
10 30 g
11 40 g
12 50 g
13 60 g
14 70 g
15 80 g
Table 15. Valid output conditions for TPMS_READ_ACCELERATION_X
u8Status Value Measurement Value Condition
$08 $03FF Uncompensated acceleration reading outside of valid range (high).
$08 $0000 Uncompensated acceleration reading outside of valid range (low).
$28 $03FF Uncompensated acceleration reading outside of valid range (high), and LVWF set.
$28 $0000 Uncompensated acceleration reading outside of valid range (low), and LVWF set.
$80 $0000 Uncompensated acceleration reading not acquired
$A0 $0000 Uncompensated acceleration reading not acquired, and LVWF set.
$00 Between $0001 - $03FE Valid uncompensated acceleration reading.
$20 Between $0001 - $03FE Valid uncompensated acceleration reading, but LVWF set