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FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide, Rev. 2.1
22
Freescale Semiconductor, Inc.
Firmware Functions
•
Input Parameters:
— UINT8 u8FiltSelect: If non-zero, 250-Hz filter enabled. Otherwise, 500-Hz filter selected.
— UINT8* u8Offset: Pointer to initial step to load. Valid offset steps range from 0 - 15 and are
described in the device's data sheet. An updated offset value is returned at the end of the
function. In case the acceleration is too high or too low and function has run out of offset steps,
a value of 255 ("0 - 1") or 16 ("15 + 1") shall be returned.
— UINT16* Pointer to the Universal Uncompensated Measurement Array. Uncompensated
acceleration will be updated accordingly.
•
Returns
:
— UINT8 u8Status: Refer to TPMS_READ_ACCELERATION_Z for more information on the
format of this status byte.
3.2.13
UINT8 TPMS_COMP_ACCELERATION_Z(UINT16 *u16CompAccel,
UINT16* u16UUMA)
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Description:
Performs an 9-bit compensated acceleration measurement. It is the user’s
responsibility to ensure that updated and valid uncompensated voltage, temperature and
acceleration readings are available in the UUMA for this routine to return a meaningful value.
— If u16CompAccel rails low, u16CompAccel will be forced to 1 and the “over/underflow” status
flag will be set.
— If u16CompAccel rails high, u16CompAccel will be forced to $1FE and the “over/underflow”
status flag will be set.
— If the passed uncompensated voltage measurement is estimated to be under the guaranteed
operational region, the routine will set the “Voltage” status flag. The accuracy of the returned
value is not guaranteed.
— For repeatability data, refer to theFXTH87xxxx family of data sheets.
•
Stack size:
55 bytes
•
Approx. Duration:
955 usec
•
Power Management:
This function executes entirely in RUN mode.
•
Interrupt Management:
This function does not await interrupts. It is not affected by interrupts
either.
•
Resources:
UUMA.
•
Input Parameters:
— UINT16 *u16Accel: Updated 9-bit compensated acceleration.
— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described
). Uncompensated voltage, temperature and acceleration will be taken from this
array.
•
Returns
:
— UINT8 u8Status: Valid error flags/outputs are described in