FXTH870xD
Sensors
Freescale Semiconductor, Inc.
83
10.6
Measurement Firmware
The firmware for making measurements is comprised of two function calls as described in
. Each measurement is a
combination of a “read” that returns the raw ADC output data and a “comp” routine which compensates that raw reading based
on information contained in the Universal Uncompensated Measurement Array (UUMA) assigned in RAM memory.
The read routines fill specific locations in the UUMA with raw data; but the compensation routines depend what is already present
in the UUMA as shown in the data flow in
Figure 57
.
The user therefore has the option to decide how often each measurement (and its component terms) are made. The resulting
power consumption is then the sum of using these components are defined in the electrical specifications in
A typical flow for a compensated pressure measurement would be:
1.
Call the TPMS_READ_PRESSURE routine which yields a raw pressure value and fills the UUMA with this data.
2.
Call the TPMS_READ_TEMPERATURE routine which yields a raw temperature value and fills the UUMA with this
data.
3.
Call the TPMS_READ_VOLTAGE routine which yields a raw voltage value and fills the UUMA with this data.
4.
Call the TPMS_COMP_PRESSURE routine which then takes the raw pressure, temperature and voltage values from
the UUMA and compensates to provide a true pressure reading to the accuracy as specified in
.
Содержание FXTH870 D Series
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