Firmware Functions
FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide, Rev. 2.1
Freescale Semiconductor, Inc.
19
3.2.9
UINT8 TPMS_READ_DYNAMIC_ACCEL_X(UINT8 u8Filter, UINT8*
u8Offset, UINT16* u16UUMA)
•
Description:
This function automatically executes a TPMS_READ_ACCELERATION_X
measurement with a given initial dynamic offset. If the result is too high or too low, it will change
the dynamic offset value and re-execute TPMS_READ_ACCELERATION_X until a) the result is
valid or b) the result is railed high or low and there are no more offset steps. Offset and
uncompensated acceleration inside the UUMA are updated.
•
Stack size:
48 bytes
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Approx. Duration:
29065 usec from one extreme to the center; 2816 usec best case.
•
Power Management:
This function requires the core to be configured for STOP4 mode and
running at full bus speed.
•
Interrupt Management:
This function utilizes the ADC interrupt to wake-up from STOP mode.
•
Resources:
SMI, ADC, internal bond wires.
•
Input Parameters:
— UINT8 u8FiltSelect: If non-zero, 250-Hz filter enabled. Otherwise, 500-Hz filter selected.
— UINT8* u8Offset: Pointer to initial offset level to load into SMI according to
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
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Returns
:
— UINT8 u8Status: Refer to TPMS_READ_ACCELERATION_X for more information on the
format of this status byte.
3.2.10
UINT8 TPMS_COMP_ACCELERATION_X(UINT16 *u16CompAccelX,
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 the FXTH87xxxx family of data sheets.
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Stack size:
55 bytes
•
Approx. Duration:
955 usec
