Freescale Semiconductor FXTH87 12 Series, FXTH87 11 Series Firmware User Manual

Freescale Semiconductor Document Number: FXTH87XX1XFWUG

User Guide Rev. 2.1, 10/2014

FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide

1 Introduction

This document describes the embedded firmware found
in all derivatives of the FXTH87xx11 and FXTH87xx12
devices.

The intended audience for this document is firmware
architects, developers, coders and/or testers working
with the FXTH87xx11 and FXTH87xx12 devices.

This document is divided into three sections: This
introduction, a section describing global variables and
standard formats used throughout the functions, and a
third section describing each function.

2 Globals and formats

2.1 Global variables

Table 1 summarizes all global variables used by

Freescale firmware and their locations. Developers must
account for these variables when creating new user
firmware.

Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 Globals and formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.1 Global variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.2 Measurement error format. . . . . . . . . . . . . . . . . . . . 3

2.3 Universal Uncompensated Measurement Array

(UUMA) format . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.4 Simulated SPI interface Signal Format . . . . . . . . . . 6

2.5 Rapid Decompression Event Array

(T_RDE) Format . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.6 LFR registers initialized by firmware . . . . . . . . . . . . 8

3 Firmware Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.1 Firmware jump table . . . . . . . . . . . . . . . . . . . . . . . 10

3.2 Function description . . . . . . . . . . . . . . . . . . . . . . . 11

© 2014 Freescale Semiconductor, Inc. All rights reserved.

Globals and formats

Table 1. Global variables and their locations

Name Address Reference

TPMS_CONT_ACCEL_GLOBAL_VARIABLE $8E Section 2.1.2

TPMS_INTERRUPT_FLAG $8F Section 2.1.1

2.1.1 TPMS_INTERRUPT_FLAG

This global variable keeps track of interrupts that have occurred. FXTH87xx11 and FXTH87xx12
Embedded Firmware uses it to keep track of expected interrupts. It can also be utilized by the user for its
own purposes.

The TPMS_INTERRUPT_FLAG is not cleared automatically. Users must clear this variable after
power-on-reset.

Table 2 shows the TPMS_INTERRUPT_FLAG format. The trigger condition column describes what is

necessary for that flag to be set.

Table 2. TPMS_INTERRUPT_FLAG format and trigger conditions

Flag BIT Trigger condition

LVD Interrupt 7 LVD interrupt entered.

PWU Interrupt 6 PWU interrupt entered.

TOF Interrupt 5 TOF interrupt entered.

LFR Error Interrupt 4 LFR interrupt entered and LFERF bit of the LFS register is set.

ADC Interrupt 3 ADC interrupt entered.

LFR Interrupt 2 LFR interrupt entered and LFERF bit of the LFS register is clear.

RTI Interrupt 1 RTI interrupt entered.

KBI Interrupt 0 KBI interrupt entered.

TPMS_INTERRUPT_FLAG is 1 byte long and is located at address $8F. Users must account for this
variable when developing for the FXTH87xx11 and FXTH87xx12.

2.1.2 TPMS_CONT_ACCEL_GLOBAL_VARIABLE

TPMS_CONT_ACCEL_GLOBAL_VARIABLE is 1 byte long and is located at address $8E. Users must
account for this variable when developing for the
contents of said variable as long as it is not overwritten. It is used internally by the TPMS_READ_ACCEL
family of functions and its purpose it to communicate the next measurement’s sampling rate when the u8Avg
argument is set to a value greater than 2.

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FXTH87xx11 and FXTH87xx12, and can ignore the

Globals and formats

2.2 Measurement error format

2.2.1 Definition of Signal Ranges

Each measured parameter (pressure, voltage, temperature, and acceleration) results from an ADC
conversion of an analog signal. This ADC result may then be passed by the firmware to the application
software as either the raw ADC result or further compensated and scaled for an output between one and
the maximum digital value minus one. The minimum digital value of zero and the maximum digital value
are reserved as error codes.

The signal ranges and their significant data points are shown in Figure 1. In this definition the signal source
would normally output a signal between S
variations this signal may increase its range to S
the supply rails, so that the ADC will convert it to a range of digital numbers between 0 and 1023 (or 0 and
4095 in the case of temperature readings). These digital numbers will have corresponding D
D

INHI

, D

INMAX

values. The ADC digital value is taken by the firmware and compensated and scaled to

give the required output code range.

INLO

and S

INMIN

. Due to process, temperature and voltage

INHI

to S

INMAX

. In all cases the signal will be between

INMIN

, D

INLO

,

Digital input values below D

INMIN

and above D

INMAX

are immediately flagged as being out of range and

generate error bits and the output is forced to the corresponding railed-high or railed-low values.
Digital values below D

(but above D

INLO

INMIN

) or above D

(but not D

INHI

INMAX

) will most likely cause
an output that would be less than 1 or greater than 510, respectively . These cases are considered underflow
or overflow , respectively. Underflow results will be forced to a value of 1. Overflow results will be forced
to a value of 510.

Digital values between D

INLO

and D

will normally produce an output between 1 to 510 (for a 9-bit

INHI

result). In some isolated cases due to compensation calculations and rounding the result may be less than
1 or greater than 510, in which case the underflow and overflow rule mentioned above is used.

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Globals and formats

SENSOR
ANALOG

ADC RAW

DIGITAL

CALCULATED

DIGITAL

(9-BIT EXAMPLE)

(10-BIT CONVERSION)

VOLTAGE

SIGNAL

SOURCE

ADC

FIRMWARE

ROUTINE

511
510

0

1

256

0

1023

512

V

DD

/2

V

DD

V

DD

S

INMAX

S

INHI

S

INMIN

S

INLO

D

INMAX

D

INHI

D

INLO

D

INMIN

NORMAL CASE

UNDERFLOW

LOWER ERROR CASE

FORCE
OUTPUT
TO ZERO

CASE

OVERFLOW

CASE

FORCE
OUTPUT
TO 511

UPPER ERROR CASE

Figure 1. Measurement Signal Range Definitions

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Globals and formats

2.2.2 Error Status Format

FXTH87xx11 and FXTH87xx12 Embedded Firmware functions that return a status byte commonly do so
using the error fields described in Table 3.

Table 3. Error Status Fields

Field Description

ADC Error - This status bit indicates an error was detected when performing an ADC test within the

BIT7 - ADCERR

BIT6 - TERR

BIT5 - VERR

BIT4 - AZERR

BIT3 - AXERR

BIT2 - PERR

BIT1 - BONDERR

BIT0 - OVFLOW

TPMS_WIRE_AND_ADC_CHECK routine.
0 ADC operating as expected.
1 ADC returned unexpected reading.

Temperature Measurement Error- This status bit indicates an error was detected by a ADC
reading of the temperature sensor that is outside of the normally accepted range.

0 Temperature error not detected in last firmware subroutine call.
1 Temperature error detected in last firmware subroutine call.

Voltage Measurement Error- This status bit indicates an error was detected by a ADC reading of
the voltage reference that is outside of the normally accepted range.

0 Voltage error not detected in last firmware subroutine call.
1 Voltage error detected in last firmware subroutine call.

Z-Axis Accelerometer Measurement Error (if applicable)- This status bit indicates an error was
detected by a bonding wire failure to the g-cell or a ADC reading of the Z-axis accelerometer that is
outside of the normally accepted range.

0 Acceleration error not detected in last firmware subroutine call.
1 Acceleration error detected in last firmware subroutine call.

X- Axis Accelerometer Measurement Error (if applicable)- This status bit indicates an error was
detected by a bonding wire failure to the g-cell or a ADC reading of the X-axis accelerometer that is
outside of the normally accepted range.

0 Acceleration error not detected in last firmware subroutine call.
1 Acceleration error detected in last firmware subroutine call.

Pressure Measurement Error- This status bit indicates an error was detected by a parity fault in
the P-Chip trim, bonding wire failure to the P-Chip or a ADC reading of the pressure that is outside
of the normally accepted range.

0 Pressure error not detected in last firmware subroutine call.
1 Pressure error detected in last firmware subroutine call.

Bond Wire Error- This status bit indicates an error was detected in any of the bond wire checks of
the g-cell or P-cell.

0 Bond wire error not detected in last firmware subroutine call.
1 Bond wire error detected in last firmware subroutine call

Calculation Overflow/Underflow- This status bit indicates that a compensated measurement of
pressure, temperature, voltage or acceleration resulted in a digital output code outside of the
expected range. The output value will be clipped to the nearest highest or lowest allowed value and
the status bit will be set.

0 Overflow/underflow not detected in last firmware subroutine call.
1 Overflow/underflow detected in last firmware subroutine call.

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Globals and formats

2.3 Universal Uncompensated Measurement Array (UUMA) format

The FXTH87xx11 and FXTH87xx12’s measurement routines are divided into two subsets: routines that
return uncompensated measurements, and routines that take uncompensated measurements as arguments
and return compensated measurements.

In order to be consistent and keep the number of CPU cycles down, all uncompensated measurement
routines will return data following the array format described in Table 4, and all compensating routines
will take data from the same array.

Table 4. Universal Uncompensated Measurement Array

Index Content

0 Uncompensated Voltage

1 Uncompensated Temperature

2 Uncompensated Pressure

3 Uncompensated X-Axis Acceleration

4 Uncompensated Z-Axis Acceleration

This array is referred to as Universal Uncompensated Measurement Array (UUMA). It can be located
anywhere the user decides.

Each element must be 16-bits long (two bytes) regardless of what the actual bit-width of the measurement
is.

Each individual uncompensated measurement routine will only update its corresponding item. For
example, calling the TPMS_READ_VOL TAGE routine will only modify the voltage element of the array .
The rest will remain unchanged.

Compensation routines do not modify any elements in the UUMA.

2.4 Simulated SPI interface Signal Format

The FXTH87xx11 and FXTH87xx12 include three routines (TPMS_MSG_INIT, TPMS_MSG_READ
and TPMS_MSG_WRITE) that, when used together, allow the user to perform serial communication with
the device through a simulated SPI interface.

The following assumptions are made:

• Only two pins are used: PTA0 for data (both incoming and outgoing) and PTA1 for clock. No slave
select is included by default, but the user may use any other pin if required.

• The data pin has a pull-up resistor enabled.

• The FXTH87xx11 and FXTH87xx12 will be a master device (the FXTH87xx1 1 and FXTH87xx12
will provide the clock).

• Data can be read/written 8-bits at a time.

• Speed of the interface is dependant on bus clock settings.

• Data is transferred MSB first.

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Globals and formats

PTA0

PTA1

Write
MSB

...

Write Write WriteRead Read Read

Write
LSB

Read
MSB

Write Read Read

LSB

...

• A single line will be used for both sending and receiving data (BIDIROE = SET according to
Freescale nomenclature).

— At the clock’ s rising edge, the master will place data on the pin. It will be valid until the clock’ s

falling edge. The slave must not drive the line during this period.

— At the clock’s falling edge, the master will make the data pin an input and will “listen” for data.

The slave must then place data on the data line until the clock’s rising edge.

• Clock Polarity = 0 (Normally low).

• Clock Phase = 1 (First half is high).

Figure 2 shows the details of the simulated SPI interface.

Figure 2. Description of the physical layer on the FXTH87xx11 and FXTH87xx12 Simulated SPI interface

For further information on the use of the Simulated SPI interface routines, refer to Section 3.2.30,

Section 3.2.31, and Section 3.2.32.

2.5 Rapid Decompression Event Array (T_RDE) Format

The FXTH87xx11 and FXTH87xx12 includes a routine called TPMS_RDE_ADJUST_PRESSURE that
requires a pointer to an array of elements using a custom format called T_RDE. Said format is easily
manageable using a typedef instruction as shown in Example 1.

Example 1. Sample typedef for a T_RDE array

typedef struct
{
UINT16 u16CompPress; /* I/O 9-bit Compensated pressure reading */
UINT8 u8ElapsedTime; /* I Elapsed time from previous reading */
UINT16 u16WAvg; /* O Weighed average for running pressure */
UINT8 u8PRes; /* O 8-bit pressure reserve value */
UINT8 u8PMin; /* O 8-bit minimum pressure value */
UINT8 u8RDEStatusFlags; /* O Contains flags for Plock and RDE Event */
UINT16 u16RDEBailTimeOut; /* O Seconds to 60 mins bail-out */
UINT8 u8RDETimeToAvg; /* O Seconds to next averaging event */
} T_RDE;

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Globals and formats

As shown by the comments, only the u16CompPress and u8ElapsedTime elements of this array should be
edited by the user; the rest will be updated by the TPMS_RDE_ADJUST_PRESSURE function.

In order for TPMS_RDE_ADJUST_PRESSURE to work correctly , the T_RDE variable must be declared
as a global and must reside in an NVM location.

For more information on TPMS_RDE_ADJUST_PRESSURE, refer to Section 3.2.47.

2.6 LFR registers initialized by firmware

Some LFR registers are touched by firmware when taking the reset vector and before giving control to the
user. The goal of this action is to configure the LFR module in the best-known configuration for
Manchester-encoded reception.

LFR registers will be configured differently depending on the user-selected sensitivity. Table 5 and

Table 6 describe these settings.

Table 5. Customer-configurable TPMS7 LF Registers with SENS = 1

Page-0 Bit name

Register name 7 6 5 4 3 2 1 0

LFCTL1 LFEN SRES CARMOD PAGE IDSEL SENS

LFCTL2 LFSTM LFONTM

LFCTL3 LFDO TOGMOD SYNC LFCDTM

LFCTL4 LFDRIE LFERIE LFCDIE LFIDIE DECEN VALEN TIMOUT

LFS LFDRF LFERF LFCDF LFIDF LFOVF LFEOMF LPSM LFIAK

LFDATA RXDATA

LFIDL ID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0

LFIDH ID15 ID14 ID13 ID12 ID11 ID10 ID9 ID8

Page-1 Bit name

Register name 7 6 5 4 3 2 1 0

LFCTL1 LFEN SRES CARMOD PAGE IDSEL SENS = 1

LFCTRLE

LFCTRLD

LFCTRLC

LFCTRLB

LFCTRLA

TRIM1

TRIM2

— — — — — 0 0 0

1 0DEQS1 1 1 0 0

0 0 0 1 AZEN LOWQ DEQEN

1 1 LFFAF LFCAF LFPOL 1 1 0

— — — —LFCC

— — — — — — — —

— — — — — — —

Shaded cells show register touched by firmware; loaded value is displayed.

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Globals and formats

Table 6. Customer-configurable TMPS and LF Register with SENS = 2

Page-0 Bit name

Register name 7 6 5 4 3 2 1 0

LFCTL1 LFEN SRES CARMOD PAGE IDSEL SENS

LFCTL2 LFSTM LFONTM

LFCTL3 LFDO TOGMOD SYNC LFCDTM

LFCTL4 LFDRIE LFERIE LFCDIE LFIDIE DECEN VALEN TIMOUT

LFS LFDRF LFERF LFCDF LFIDF LFOVF LFEOMF LPSM LFIAK

LFDATA RXDATA

LFIDL ID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0

LFIDH ID15 ID14 ID13 ID12 ID11 ID10 ID9 ID8

Page-1 Bit name

Register name 7 6 5 4 3 2 1 0

LFCTL1 LFEN SRES CARMOD PAGE IDSEL SENS = 2

LFCTRLE

LFCTRLD

LFCTRLC

LFCTRLB

LFCTRLA

TRIM1

TRIM2

— — — — — 0 0 0

1 0DEQS1 1 1 0 0

0 0 0 1 AZEN LOWQ DEQEN

1 1 LFFAF LFCAF LFPOL 1 1 0

— — — —LFCC

— — — — — — — —

— — — — — — — —

Shaded cells show register touched by firmware; loaded value is displayed.

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Firmware Functions

3 Firmware Functions

3.1 Firmware jump table

The FXTH87xx11 and FXTH87xx12 devices contain an embedded firmware function jump table to allow
programmers to reference any function through a function pointer to an absolute address. This helps isolate
Freescale firmware from the user’s application. Table 7 shows a list of all firmware functions and their
address.

For a description of how to implement pointers to fixed addresses using the C language, please refer to
Manual_Compiler_HC08.pdf (part of the CodeWarrior package).

Table 7. FXTH87xx11 and FXTH87x x12’s Firmware Function jump table

Absolute Address Return type Function

$E000 void TPMS_RESET

$E003 UINT8 TPMS_READ_VOLTAGE

$E006 UINT8 TPMS_COMP_VOLTAGE

$E009 UINT8 TPMS_READ_TEMPERATURE

$E00C UINT8 TPMS_COMP_TEMPERATURE

$E00F UINT8 TPMS_READ_PRESSURE

$E012 UINT8 TPMS_COMP_PRESSURE

$E015 UINT8 TPMS_READ_ACCELERATION_X

$E018 UINT8 TPMS_READ_DYNAMIC_ACCEL_X

$E01B UINT8 TPMS_COMP_ACCELERATION_X

$E01E UINT8 TPMS_READ_ACCELERATION_Z

$E021 UINT8 TPMS_READ_DYNAMIC_ACCEL_Z

$E024 UINT8 TPMS_COMP_ACCELERATION_Z

$E027 UINT8 TPMS_READ_ACCELERATION_XZ

$E02A UINT8 TPMS_READ_DYNAMIC_ACCEL_XZ

$E02D UINT8 TPMS_COMP_ACCELERATION_XZ

$E030 UINT8 TPMS_READ_V0

$E033 UINT8 TPMS_READ_V1

$E036 UINT8 TPMS_LFOCAL

$E039 UINT8 TPMS_MFOCAL

$E03C void TPMS_RF_ENABLE

$E03F void TPMS_RF_RESET

$E042 void TPMS_RF_READ_DATA

$E045 void TPMS_RF_READ_DATA_REVERSE

$E048 void TPMS_RF_WRITE_DATA

$E04B void TPMS_RF_WRITE_DATA_REVERSE

$E04E void TPMS_RF_CONFIG_DATA

$E051 — Reserved

$E054 void TPMS_RF_SET_TX

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Table 7. FXTH87xx11 and FXTH87xx12’s Firmware Function jump table (continued)

Absolute Address Return type Function

$E057 void TPMS_RF_DYNAMIC_POWER

$E05A void TPMS_MSG_INIT

$E05D UINT8 TPMS_MSG_READ

$E060 UINT8 TPMS_MSG_WRITE

$E063 UINT8 TPMS_CHECKSUM_XOR

$E066 UINT8 TPMS_CRC8

$E069 UINT16 TPMS_CRC16

$E06C UINT16 TPMS_SQUARE_ROOT

$E06F void TPMS_READ_ID

$E072 void TPMS_LF_ENABLE

$E075 UINT8 TPMS_LF_READ_DATA

$E078 UINT8 TPMS_WIRE_AND_ADC_CHECK

$E07B void TPMS_FLASH_WRITE

$E07E UINT16 TPMS_FLASH_CHECK

$E081 UINT8 TPMS_FLASH_ERASE

$E084 UINT8 TPMS_FLASH_PROTECTION

$E087 — Reserved

$E08A void TPMS_MULT_SIGN_INT16

$E08D UINT16 TPMS_WAVG

$E090 UINT8 TPMS_RDE_ADJUST_PRESSURE

Firmware Functions

3.2 Function description

The following function descriptions include stack sizes and approximate duration.
Stack sizes have been calculated by executing each routine and measuring the amount of memory utilized.

Unless noted, they represent the maximum stack the function will utilize.
Duration estimates are performed on one part at room temperature. They are intended to serve as a

guideline for typical execution time.

3.2.1 void TPMS_RESET(void)

• Description: This function is called when taking the reset vector. It will reset the Stack Pointer to
the last RAM location and jump to the location stored by the user in $DFFE:DFFF. No further
initialization is performed.

• Stack size: 3 bytes

• 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: Stack

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Firmware Functions

• Input Parameters:
— None

• Returns:

— void

3.2.2 UINT8 TPMS_READ_VOLTAGE(UINT16 *u16UUMA)

• Description: Performs a 10-bit uncompensated voltage measurement and places it in the UUMA.
While waiting for the ADC to converge, this function goes into STOP4. If the ADC, for an
unexpected reason, fails to converge, this function has a built-in time-out: After five continuous
non-ADC interrupts, the function will assume a failed ADC reading, flag it accordingly, and exit.

— If the ADC value is over or under the normal operating condition, the “voltage error” status flag

will be set. The expected voltage result will be forced to either “0” or “1023.” (rail high or rail

low).
— If the ADC times out with no result, the “ADC error” status flag will be set.
— Measurements below 2.1 V are not guaranteed for accuracy.

• Stack size: 22 bytes

• Approx. Duration: 102 usec

• 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: ADC, bandgap.

• Input Parameters:

— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described

in Section 2.3). Only the 10-bit uncompensated voltage result will be updated.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 8.

Table 8. Valid output conditions for TPMS_READ_VOLTAGE

u8Status Value Measurement Value Condition

$20 $03FF Uncompensated voltage reading outside of valid range (high).

$20 $0000 Uncompensated voltage reading outside of valid range (low).

$80 Undefined Uncompensated voltage reading not acquired.

$00 Between $0001 - $03FE Valid uncompensated voltage reading.

WARNING

The Bandgap bit (BIT0 in the SPMSC1 register) must be set prior to calling
this function for results to be valid.

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Firmware Functions

3.2.3 UINT8 TPMS_COMP_VOLTAGE(UINT8 *u8CompVoltage, *UINT16 u16UUMA)

• Description: Performs an 8-bit compensated voltage measurement. It is the user’s responsibility

to ensure that updated and valid uncompensated voltage reading is available in the UUMA for this
routine to return a meaningful value.

— If Vout < 2.1 V, u8Voltage will be 1 and the “over/underflow” status flag will be set.
— Measurements below 2.1 V are not guaranteed for accuracy.
— If Vout  3.7 V, result will be $FE and the “over/underflow” status flag will be set.
— For repeatability data, refer to the FXTH87xxxx family of data sheets.

• Stack size: 31 bytes

• Approx. Duration: 204 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:

— UINT8 *u8Voltage: Updated 8-bit compensated voltage result.
— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described

in Section 2.3). Uncompensated voltage will be utilized from this array.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 9.

Table 9. Valid output conditions for TPMS_COMP_VOLTAGE

u8Status Value Measurement Value Condition

$01 $FE Compensated voltage reading outside of valid range (high).

$01 $01 Compensated voltage reading outside of valid range (low).

$00 Between $01 - $FE Valid compensated voltage reading.

3.2.4 UINT8 TPMS_READ_TEMPERATURE(UINT16 *u16UUMA)

• Description: Performs a 12-bit uncompensated temperature measurement and places it in the

UUMA. While waiting for the ADC to converge, this function goes into STOP4. If the ADC, for
an unexpected reason, fails to converge, this function has a built-in time-out: After five continuous
non-ADC interrupts, the function will assume a failed ADC reading, flag it accordingly, and exit.

— If the ADC value is over or under the normal operating condition, the “temperature error” status

flag will be set. The expected temperature result will be forced to either “0” or “4095.” (rail
high or rail low). If the LVWF (Low Voltage Warning Flag) hardware bit is set, it will flag it
accordingly as well.

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Firmware Functions

— If the ADC value is over or under the normal operating condition, the “temperature error” status

flag will be set. The expected temperature result will be forced to either “0” or “4095.” (rail
high or rail low).

— If the ADC times out with no result, the “ADC error” status flag will be set.

• Stack size: 17 bytes

• Approx. Duration: 219 usec

• 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: ADC, bandgap.

• Input Parameters:

— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described

in Section 2.3). Only the 12-bit uncompensated temperature result will be updated.

• Returns: UINT8 u8Status:Valid error flags/outputs are described in Table 10.

.

u8Status Value Measurement Value Condition

$40 $0FFF Uncompensated temperature reading outside of valid range (high).

$40 $0000 Uncompensated temperature reading outside of valid range (low).

$60 $0FFF

$60 $0000

$80 Undefined Uncompensated temperature reading not acquired.

$A0 Undefined Uncompensated temperature reading not acquired, and LVWF set.

$00 Between $0001 - $0FFE Valid uncompensated temperature reading.

$20 Between $0001 - $0FFE Valid uncompensated temperature reading, LVWF set.

Table 10. Valid output conditions for TPMS_READ_TEMPERATURE

Uncompensated temperature reading outside of valid range (high),
and LVWF set.

Uncompensated temperature reading outside of valid range (low),
and LVWF set.

WARNING

The Bandgap bit (BIT0 in the SPMSC1 register) must be set prior to calling
this function for results to be valid.

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Firmware Functions

3.2.5 UINT8 TPMS_COMP_TEMPERATURE(UINT8 *u8Temp, UINT16 *u16UUMA)

• Description: Performs an 8-bit compensated temperature measurement. It is the user’s

responsibility to ensure that updated and valid uncompensated temperature reading is available in
the UUMA for this routine to return a meaningful value.

— If Tout < -40°C, u8Temp will be 1 and the “over/underflow” status flag will be set.
— If Tout  200°C, u8Temp will be $FE and the “over/underflow” status flag will be set.

• Stack size: 30 bytes.

• Approx. Duration: 231 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:

— UINT8 *u8Temp: Updated 8-bit compensated temperature result.
— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described

in Section 2.3). Uncompensated temperature will be utilized from this array.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 11.

Table 11. Valid output conditions for TPMS_COMP_TEMPERATURE

u8Status Value Measurement Value Condition

$01 $FE Compensated temperature reading outside of valid range (high).

$01 $01 Compensated temperature reading outside of valid range (low).

$00 Between $01 - $FE Valid compensated temperature reading.

3.2.6 UINT8 TPMS_READ_PRESSURE(UINT16 *u16UUMA, UINT8 u8Avg)

• Description: Performs an 10-bit uncompensated pressure measurement and places it in the

UUMA. While waiting for the ADC to converge, this function goes into STOP4. If the ADC, for
an unexpected reason, fails to converge, this function has a built-in time-out: After five continuous
non-ADC interrupts, the function will assume a failed ADC reading, flag it accordingly , and exit.
If the LVWF (Low Voltage Warning Flag) hardware bit is set, it will flag it accordingly as well.

— If the ADC value is over or under the normal operating condition, the “pressure error” status

flag will be set. The expected pressure result will be forced to either “0” or “1023.” (rail high
or rail low).

— If the ADC times out with no result, the “ADC error” status flag will be set.

• Stack size: 26 bytes

• Approx. Duration: 2872 usec (avg of 1); 10670 usec (avg of 4).

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• 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:

— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described

in Section 2.3). Only the 10-bit uncompensated pressure result will be updated.

— UINT8 u8A vg: Number of measurements to average into one result. The value can be set to 1,

2, 4, 8, or 16.

• Returns: UINT8 u8Status: Valid error flags/outputs are described in Table 12.

.

u8Status Value Measurement Value Condition

$04 $03FF Uncompensated pressure reading outside of valid range (high).

$04 $0000 Uncompensated pressure reading outside of valid range (low).

$24 $03FF

$24 $0000

$80 $0000 Uncompensated pressure reading not acquired

$A0 $0000 Uncompensated pressure reading not acquired, and LVWF set.

$00 Between $0001 - $03FE Valid uncompensated pressure reading.

$00 Between $0001 - $03FF Valid uncompensated pressure reading, and LVWF set.

Table 12. Valid output conditions for TPMS_READ_PRESSURE

Uncompensated pressure reading outside of valid range (high), and
LVW F se t .

Uncompensated pressure reading outside of valid range (low), and
LVW F se t .

3.2.7 UINT8 TPMS_COMP_PRESSURE(UINT16 *u16CompPressure, UINT16 *u16UUMA)

• Description: Performs an 9-bit compensated pressure measurement. It is the user’s responsibility

to ensure that updated and valid uncompensated voltage, temperature and pressure readings are
available in the UUMA for this routine to return a meaningful value.

— If either the temperature or supply voltage measurements inherent to this function result in a

fault, the pressure reading will be forced to 0 and the appropriate pressure, temperature and/or
voltage flags will be set in the status flag.

— If Pout < 100 kPa, the “over/underflow” status flag will be set, and u16CompPressure will be

forced to $001.

— If Pout

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.

• Stack size: 46 bytes

 900 kPa, u16CompPressure will be $1FE and the “over/underflow” status flag will be

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• Approx. Duration: 872 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 *u16Pressure: Updated 9-bit compensated pressure result.
— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described

in Section 2.3). Uncompensated voltage, temperature and pressure will be taken from this
array.

• Returns: UINT8 u8Status: Valid error flags/outputs are described in Table 13.

Table 13. Valid output conditions for TPMS_COMP_PRESSURE

u8Status Value Measurement Value Condition

$01 $01FE Compensated pressure reading outside of valid range (high).

$01 $0001 Compensated pressure reading outside of valid range (low).

$21 $01FE

$21 $0001

$20 Between $0001 - $01FE

$00 Between $0001 - $01FE Valid compensated pressure reading.

Compensated pressure reading outside of valid range (high), and uncompensated
voltage suspected to be below valid operating range for this function.

Compensated pressure reading outside of valid range (low), and uncompensated
voltage suspected to be under below operating range for this function.

Uncompensated voltage suspected to be below valid operating range for this
function; The compensated reading is not guaranteed for accuracy.

3.2.8 UINT8 TPMS_READ_ACCELERATION_X(UINT16 *u16UUMA, UINT8 u8Avg, UINT8 u8FiltSelect, UINT8 u8DynamicOffset)

• Description: Performs an uncompensated 10-bit measurement. While waiting for the ADC to

converge, this function goes into STOP4. If the ADC, for an unexpected reason, fails to converge,
this function has a built-in time-out: After five continuous non-ADC interrupts, the function will
assume a failed ADC reading, flag it accordingly, and exit. If the LVWF (Low Voltage Warning
Flag) hardware bit is set, it will flag it accordingly as well.

— If the ADC value is over or under the normal operating condition, the “acceleration error”

status flag will be set. The expected acceleration result will be forced to either “0” or “1023.”
(rail high or rail low).

— If the ADC times out with no result, the “ADC error” status flag will be set.

• Stack size: 31 bytes

• Approx. Duration: 2901 usec (500-Hz filter, 1 reading), 4255 usec (250-Hz filter, 1 reading).

• 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.

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• 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 u8A vg: 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.

.

Table 14. u8DynamicOffset valid values

Offset when result of function is 256 counts

Offset Index

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)

810 g

920 g

10 30 g

11 40 g

12 50 g

13 60 g

14 70 g

15 80 g

assuming stand trim.

Span does not change.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 15.

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

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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

• 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 Table 14. 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_X for more information on the

format of this status byte.

3.2.10 UINT8 TPMS_COMP_ACCELERATION_X(UINT16 *u16CompAccelX, UINT16* u16UUMA)

• 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.

• Stack size: 55 bytes

• Approx. Duration: 955 usec

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• 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 *u16AccelX: Updated 9-bit compensated acceleration.
— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described

in Section 2.3). Uncompensated voltage, temperature and X-axis acceleration will be taken
from this array.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 16.

Table 16. Valid output conditions for TPMS_COMP_ACCELERATION_X

u8Status Value Measurement Value Condition

$01 $01FE Compensated acceleration reading outside of valid range (high).

$01 $0001 Compensated acceleration reading outside of valid range (low).

Compensated pressure reading outside of valid range (high), and

$21 $01FE

$21 $0001

$20 Between $0001 - $01FE

$00 Between $0001 - $01FE Valid compensated acceleration reading.

uncompensated voltage suspected to be below valid operating
range for this function.

Compensated pressure reading outside of valid range (low), and
uncompensated voltage suspected to be under below operating
range for this function.

Uncompensated voltage suspected to be below valid operating
range for this function; The compensated reading is not guaranteed
for accuracy.

3.2.11 UINT8 TPMS_READ_ACCELERATION_Z(UINT16 *u16UUMA, UINT8 u8Avg, UINT8 u8FiltSelect, UINT8 u8DynamicOffset)

• Description: Performs an uncompensated 10-bit measurement. While waiting for the ADC to

converge, this function goes into STOP4. If the ADC, for an unexpected reason, fails to converge,
this function has a built-in time-out: After five continuous non-ADC interrupts, the function will
assume a failed ADC reading, flag it accordingly, and exit. If the LVWF (Low Voltage Warning
Flag) hardware bit is set, it will flag it accordingly as well.

— If the ADC value is over or under the normal operating condition, the “acceleration error”

status flag will be set. The expected acceleration result will be forced to either “0” or “1023.”
(rail high or rail low).

— If the ADC times out with no result, the “ADC error” status flag will be set.

• Stack size: 31 bytes

• Approx. Duration: 2901 usec (500-Hz filter, 1 reading), 4255 usec (250-Hz filter, 1 reading).

• Power Management: This function requires the core to be configured for STOP4 mode and

running at full bus speed.

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• Interrupt Management: This function utilizes the ADC interrupt to wake-up from STOP mode.

• Resources: SMI, ADC, internal bond wires.

• 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 u8A vg: 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.

Valid range is 0 - 15. Refer to product specification for acceleration ranges for a given offset

step.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 17.

Table 17. Valid output conditions for TPMS_READ_ACCELERATION_X

u8Status Value Measurement Value Condition

$10 $03FF Uncompensated acceleration reading outside of valid range (high).

$10 $0000 Uncompensated acceleration reading outside of valid range (low).

$30 $03FF

$30 $0000

$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.

Uncompensated acceleration reading outside of valid range (high),
and LVWF set.

Uncompensated acceleration reading outside of valid range (low),
and LVWF set.

3.2.12 UINT8 TPMS_READ_DYNAMIC_ACCEL_Z(UINT8 u8Filter, UINT8* u8Offset, UINT16* u16UUMA)

• Description: This function automatically executes a TPMS_READ_ACCELERATION_Z

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_Z 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

• 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.

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• 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)

• 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

in Section 2.3). Uncompensated voltage, temperature and acceleration will be taken from this
array.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 18.

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Table 18. Valid output conditions for TPMS_COMP_ACCELERATION_Z

u8Status Value Measurement Value Condition

$01 $01FE Compensated acceleration reading outside of valid range (high).

$01 $0001 Compensated acceleration reading outside of valid range (low).

Compensated pressure reading outside of valid range (high), and

$21 $01FE

$21 $0001

$20 Between $0001 - $01FE

$00 Between $0001 - $01FE Valid compensated acceleration reading.

uncompensated voltage suspected to be below valid operating
range for this function.

Compensated pressure reading outside of valid range (low), and
uncompensated voltage suspected to be under below operating
range for this function.

Uncompensated voltage suspected to be below valid operating
range for this function; The compensated reading is not guaranteed
for accuracy.

3.2.14 UINT8 TPMS_READ_ACCELERATION_XZ(UINT16 *u16UUMA, UINT8 u8Avg, UINT8 u8FiltSelect, UINT8 u8DynamicOffsetX, UINT8 u8DynamicOffsetZ)

• Description: Performs an uncompensated 10-bit measurement. While waiting for the ADC to

converge, this function goes into STOP4. If the ADC, for an unexpected reason, fails to converge,
this function has a built-in time-out: After five continuous non-ADC interrupts, the function will
assume a failed ADC reading, flag it accordingly, and exit.

— If the ADC value is over or under the normal operating condition, the “acceleration error”

status flag will be set. The expected acceleration result will be forced to either “0” or “1023.”
(rail high or rail low).

— If the ADC times out with no result, the “ADC error” status flag will be set.

• Stack size: 34 bytes

• Approx. Duration: 5744 usec (500-Hz filter, 1 reading), 8477 usec (250-Hz filter, 1 reading).

• 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:

— 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 u8A vg: Number of measurements to average into one result. The value can be set to 1,

2, 4, 8, 16, or 32.
— UINT8 u8FiltSelect: If non-zero, 250-Hz filter enabled. Otherwise, 500-Hz filter selected.
— UINT8 u8DynamicOffsetX: Selects the offset setting for the appropriate acceleration reading.

Refer to Table 14 for more information.
— UINT8 u8DynamicOffsetZ: Selects the offset setting for the appropriate acceleration reading.

Refer to Table 17 for more information.

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• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 19.

Table 19. Valid output conditions for TPMS_READ_ACCELERATION_XZ

u8Status V alue Measurement Value Condition

$08 $03FF Uncompensated X acceleration reading outside of valid range (high).

$08 $0000 Uncompensated X acceleration reading outside of valid range (low).

$28 $03FF

$28 $0000

$10 $03FF Uncompensated Z acceleration reading outside of valid range (high).

$10 $0000 Uncompensated Z acceleration reading outside of valid range (low).

$30 $03FF

$30 $0000

$18 $03FF Uncompensated X and Z acceleration readings outside of valid range (high).

$18 $0000 Uncompensated X and Z acceleration readings outside of valid range (low).

$38 $03FF

$38 $0000

$80 Undefined Uncompensated acceleration reading not acquired.

$A0 Undefined 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.

Uncompensated X acceleration reading outside of valid range (high), and LVWF
set.

Uncompensated X acceleration reading outside of valid range (low,) and LVWF
set.

Uncompensated Z acceleration reading outside of valid range (high), and LVWF
set.

Uncompensated Z acceleration reading outside of valid range (low), and LVWF
set.

Uncompensated X and Z acceleration readings outside of valid range (high), and
LVW F se t .

Uncompensated X and Z acceleration readings outside of valid range (low), and
LVW F se t .

3.2.15 UINT8 TPMS_READ_DYNAMIC_ACCEL_XZ(UINT8 u8Filter, UINT8* u8OffsetX, UINT8* u8OffsetZ, UINT16* u16UUMA)

• Description: This function automatically executes a TPMS_READ_DYNAMIC_ACCEL_X

measurement, followed by a TPMS_READ_DYNAMIC_ACCEL_Z measurement with given
initial dynamic offsets. Refer to the description of these functions for more information.

• Stack size: 60 bytes

• Approx. Duration: 50240 usec from one extreme to the center; 8200 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.

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— UINT8* u8OffsetX: Pointer to initial offset level to load into SMI according to Table 14. An

updated offset value is returned at the end of the function.

— UINT8* u8OffsetZ: Pointer to initial offset level to load into SMI according to Table 17. An

updated offset value is returned at the end of the function.

— UINT16* Pointer to the Universal Uncompensated Measurement Array. Uncompensated

acceleration for both axes will be updated accordingly.

• Returns:

— UINT8 u8Status: Refer to TPMS_READ_ACCELERATION_Z for more information on the

format of this status byte.

3.2.16 UINT8 TPMS_COMP_ACCELERATION_XZ(UINT16 *u16CompAccel, UINT16* u16UUMA)

• Description: This function internally calls TPMS_COMP_ACCELERATION_X followed by

TPMS_COMP_ACCELERATION_Z. It places the compensated results in a 2-word array. For
more information, refer to the functions afore mentioned.

• Stack size: 60 bytes

• Approx. Duration: 1910 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 *u16CompAccel: Updated 9-bit compensated X-axis acceleration followed by Z-axis

acceleration.

— UINT16 *u16UUMA: Pointer to Universal Uncompensated Measurement Array (as described

in Section 2.3). Uncompensated voltage, temperature and acceleration will be taken from this
array.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 20.

Table 20. Valid output conditions for TPMS_COMP_ACCELERATION_XZ

u8Status V alue Measurement Value Condition

$01 $01FE Compensated acceleration reading outside of valid range (high).

$01 $0001 Compensated acceleration reading outside of valid range (low).

$21 $01FE

$21 $0001

$20 Between $0001 - $01FE

$00 Between $0001 - $01FE Valid compensated acceleration reading.

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Compensated pressure reading outside of valid range (high), and uncompensated
voltage suspected to be below valid operating range for this function.

Compensated pressure reading outside of valid range (low), and uncompensated
voltage suspected to be under below operating range for this function.

Uncompensated voltage suspected to be below valid operating range for this
function; The compensated reading is not guaranteed for accuracy.

Firmware Functions

3.2.17 UINT8 TPMS_READ_V0(UINT16 *u16Result, UINT8 u8Avg)

• Description: Performs an 10-bit uncompensated measurement at pin PTA0.

• Stack size: 23 bytes

• Approx. Duration: 107 usec

• 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: ADC, PTA0.

• Input Parameters:

— UINT16 *u16Result: Updated 10-bit uncompensated measurement.
— UINT8 u8A vg: Number of measurements to average into one result. The value can be set to 1,

2, 4, 8, or 16.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 21.

Table 21. Valid output conditions for TPMS_READ_V0 and TPMS_READ_V1

u8Status Value Measurement Value Condition

$01 $0000 Reading not acquired.

$00 Between $0000 - $03FE Valid reading.

3.2.18 UINT8 TPMS_READ_V1(UINT16 *u16Result, UINT8 u8Avg)

• Description: Performs an 10-bit uncompensated measurement at pin PTA1.

• Stack size: 23 bytes

• Approx. Duration: 107 usec

• 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: ADC, PTA1.

• Input Parameters:

— UINT16 *u16Result: Updated 10-bit uncompensated measurement.
— UINT8 u8A vg: Number of measurements to average into one result. The value can be set to 1,

2, 4, 8, or 16.

• Returns:

— UINT8 u8Status: Valid error flags/outputs are described in Table 21.

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3.2.19 UINT8 TPMS_LFOCAL(void)

• Description: Performs PWU clock calibration. The wake-up and periodic reset time can be

calibrated more accurately by using the TPMS_LFOCAL firmware subroutine. This subroutine
turns on the RFM crystal oscillator and feeds a 500-Hz clock via the DX signal to the TPM1 for
one cycle of the LFO. The measured time is used to calculate the correct value for the
WDIV0:5-bits for a WCLK period of 1 second. The resulting value for use in the WDIV0:5-bits is
returned in the accumulator . The user can decide whether to load the value to the WDIV0:5-bits or
store for future reference. The TPMS_LFOCAL subroutine cannot be used while the RFM is
transmitting or the TPM1 is being used for another task. This routine will also consume more
power due to the crystal oscillator running. This function accesses and writes data to the SIMOPT2
register . Since some of the bits in this register are write-once-only, it should be configured prior to
calling this routine.

• Stack size: 9 bytes

• Approx. Duration: 1747 usec

• Power Management: This function executes entirely in RUN mode.It requires the MCU to be

configured for 4 MHz bus clock.

• Interrupt Management: This function does not await any interrupts. It WILL be affected by

interrupts.

• Resources: TPM, SIMOPT2, RFM

• Input Parameters:

— None

• Returns:

— UINT8 u8WDIV: WDIV compensated value.

WARNING

This routine writes to SIMOPT2. Any configuration involving this register
must be performed before calling this routine.

3.2.20 UINT8 TPMS_MFOCAL(void)

• Description: Performs MFO cross-check verification. This function will measure the bus clock

relative to Dx, but first executes a test to verify the presence of the external XTAL. When error is
zero, it returns “128.” Any deviation from this value should be considered an error. This result can
then be used to estimate the error in the RFBT setting. The TPMS_MFOCAL subroutine cannot be
used while the RFM is transmitting or the TPM1 is being used for another task. This function
accesses and writes data to the SIMOPT2 register. Since some of the bits in this register are
write-once-only, it should be configured prior to calling this routine.

• Stack size: 9 bytes

• Approx. Duration: 1825 usec

• Power Management: This function executes entirely in RUN mode. It requires the MCU to be

configured for 4 MHz bus clock.

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• Interrupt Management: This function does not await any interrupts. It WILL be affected by

interrupts.

• Resources: TPM, SIMOPT2, RFM

• Input Parameters:

— None

• Returns:

— UINT8 u8Error: 128 when no error is found. Each LSB away from this value is equal to a

0.78% error . For example, if u8Error = 125, MFO has a -2.34% error , or is running at 122 kHz.
255 is reserved as an error code for when the external XTAL is not present.

WARNING

This routine writes to SIMOPT2. Any configuration involving this register
must be performed before calling this routine.

3.2.21 void TPMS_RF_ENABLE(UINT8 u8Switch)

• Description: This function enables or disables the RF module in the FXTH87xx11 and

FXTH87xx12 and transfers adequate PLL trim data to the module. It should be called prior to any
other RF operation.

• Stack size: 4 bytes

• Approx. Duration: 378 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will be affected by

interrupts.

• Resources: SIMOPT1, RFM

• Input Parameters:

— UINT8 u8Switch: Enable (non-zero) or disable (zero) RFM.

• Returns:

— void.

WARNING

This routine writes to SIMOPT1. Any configuration involving this register
must be performed before calling this routine.

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3.2.22 void TPMS_RF_RESET(void)

• Description: This function sends a master reset to the RFM and reloads PLL trim values into the

module. It requires the RFM to have been enabled previously.

• Stack size: 3 bytes

• Approx. Duration: 228 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: RFM

• Input Parameters:

— None

• Returns:

— void

3.2.23 void TPMS_RF_READ_DATA(UINT8 u8Size, UINT8 *u8RAMBuffer, UINT8 u8RFMBuffer)

• Description: This function reads several consecutive bytes from the dedicated RFM buffer

registers and copies them to a given address in RAM. It assumes that BUFF0 is location “0”. The
data is transferred from the LSB bit of the RFM data registers to the LSB of the target memory
address (standard data bit order). This function manages the RFM’s buffer paged memory.

— In case the required buffer address is out of bounds, the routine will return “0” for that location.

• Stack size: 9 bytes

• Approx. Duration: 194 usec (for 8 bytes, switching pages included).

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: RFM

• Input Parameters:

— UINT8 u8Size: Number of bytes to read.
— UINT8 *u8RamBuffer: Target memory location.
— UINT8 u8RFMBuffer: Buffer register (0 to 31) to read.

• Returns:

— void

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3.2.24 void TPMS_RF_READ_DATA_REVERSE(UINT8 u8Size, UINT8 *u8RAMBuffer, UINT8 u8RFMBuffer)

• Description: This function reads several consecutive bytes from the dedicated RFM buffer

registers and copies them to a given address in RAM. It assumes that BUFF0 is location “0”. The
data is transferred from the LSB bit of each byte of the RFM data registers to the MSB of each of
the bytes of the target memory address (reversed data bit order). This function manages the RFM’ s
buffer paged memory.

— In case the required buffer address is out of bounds, the routine will return “0” for that location.

• Stack size: 10 bytes

• Approx. Duration: 236 usec (for 8 bytes, switching pages included).

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: RFM

• Input Parameters:

— UINT8 u8Size: Number of bytes to read.
— UINT8 *u8RamBuffer: Target memory location.
— UINT8 u8RFMBuffer: Buffer register (0 to 31) to read.

• Returns:

— void

3.2.25 void TPMS_RF_WRITE_DATA(UINT8 u8Size, UINT8 *u8RAMBuffer, UINT8 u8RFMBuffer)

• Description: This function copies several consecutive bytes from RAM into the dedicated RFM

Output Buffer. It assumes that BUFF0 is location “0”. The data is transferred from the LSB bit of
RAM to the LSB of the RFM data register (standard data bit order). This function manages the
RFM’s buffer paged-memory.

— In case the destination buffer address is out of bounds, the register value will not be written.

• Stack size: 8 bytes

• Approx. Duration: 182 usec (for 8 bytes, switching pages included).

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: RFM

• Input Parameters:

— UINT8 u8Size: Number of bytes to write.
— UINT8 *u8RamBuffer: Source memory location.
— UINT8 u8RFMBuffer: Starting buffer register (0 to 31) to write.

• Returns:

— void

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3.2.26 void TPMS_RF_WRITE_DATA_REVERSE(UINT8 u8Size, UINT8 *u8RAMBuffer, UINT8 u8RFMBuffer)

• Description: This function copies several consecutive bytes from RAM into the dedicated RFM

Output Buffer. It assumes that BUFF0 is location “0”. The data is transferred from the LSB bit of
each byte in RAM to the MSB of each byte in the RFM data register (reversed data bit order). This
function manages the RFM’s buffer paged-memory.

— In case the destination buffer address is out of bounds, the register value will not be written.

• Stack size: 9 bytes

• Approx. Duration: 242 usec (for 8 bytes, switching pages included).

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: RFM

• Input Parameters:

— UINT8 u8Size: Number of bytes to write.
— UINT8 *u8RamBuffer: Source memory location.
— UINT8 8uRFMBuffer: Starting buffer register (0 to 31) to write.

• Returns:

— void

3.2.27 void TPMS_RF_CONFIG_DATA(UINT16 *u16RFParam)

• Description: This function is included for backward compatibility with the MPXY8300. This

function configures the RFM for transmission. It does not configure inter-frame wait times, which
must be configured manually.

• Stack size: 4 bytes

• Approx. Duration: 32 usec.

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: RFM

• Input Parameters:

— UINT16* u16RFParam Format as described in Table 22.

Table 22. u16RFParam Array format

Index Description

0 Refer to Table 23 for description.

1 PLLA value.

2 PLLB value

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Table 23. Description of Element 0 in the u16RFParam Array

Bits Description

15:8 Prescaler value. Described in Data Sheet as RFCR0.

7 End Of Message- If ‘1’, EOM is set, if ‘0’, it’s not set.

6 Polarity Bit - If ‘1’, polarity is inverted, If ‘0’, it is non-inverted.

5:4 Not used.

2:3 Encoding value - Refer to the product spec for more information.

1 Frequency selection - If ‘1’, RFM is configured for 434 MHz, if ‘0’, it is configured for 315 MHz.

0 Modulation - If ‘1’, RFM is configured for FSK, if ‘0’ it is configured for OOK.

• Returns:

— void

3.2.28 void TPMS_RF_SET_TX(UINT8 u8BufferSize)

• Description: This function allows the RFM to transmit data previously loaded in the buffer. It

should be called after the RF module has been enabled and configured.

• Stack size: 3 bytes

• Approx. Duration: 12 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: RFM

• Input Parameters:

— UINT8 u8BufferSize: Number of bits in the buffer -1 (for example, to transmit one bit,

u8BufferSize should equal 0).

• Returns:

— void

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3.2.29 void TPMS_RF_DYNAMIC_POWER(UINT8 u8CompT, UINT8 u8CompV, UINT8* pu8PowerManagement)

• Description: Depending on the passed parameters, this function can:

— Force the RF power setting (RFCFR2_PWR) to a passed value (when BIT5 of

u8PowerManagement is clear).

— Set the RF power setting (RFCFR2_PWR) dynamically based on voltage, temperature, and

current carrier frequency (when BIT5 of u8PowerManagement is set). The power domains for
this function are described in the FXTH87xxxx family of data sheets.

— Similar to the case above, the user can specify a target power region with an offset.

• Stack size: 21 bytes

• Approx. Duration: 140 usec when calculating dynamic power; 20 usec when power setting is

passed.

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: RFM

• Input Parameters:

— UINT8 u8CompT: Compensated temperature reading
— UINT8 u8CompV: Compensated voltage reading
— UINT8* pu8PowerManagement: This is a pointer to an array of five elements as described

below.

Table 24. *pu8PowerManagement format

Index Value Description

0 Dynamic Compensation switch as described in Table 25.

1 Offset step for power target when temperature is lower than 0°C. Negative values admitted.

2 Offset step for power target when temperature is lower than 25°C and higher than 0°C.Negative values admitted.

3

4 Offset step for power target when temperature is higher than 60°C. Negative values admitted.

BIT Description

MSB Not used.

BIT6 Not used.

BIT5

BIT4:0 When BIT5 is clear, the value passed here will be used to set the RF power step directly.

Offset step for power target when temperature is lower than 60°C and higher than 25°C. Negative values
admitted.

Table 25. pu8PowerManagement[0] format

Dynamic compensation enable.
If set, the function will decide what the optimal power setting is based on voltage and temperature; In this case,

values stored in the array will be added to the found target.
If clear, BIT4:0 will be used to set the power level directly.

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• Returns:

— void

WARNING

The RF Module must be turned on prior to calling this routine.

3.2.30 void TPMS_MSG_INIT(void)

• Description: This function is to be called before using any MSG routine. It initializes PTA1 and

PTA0 to their correct initial state for a simulated SPI.

• Stack size: 2 bytes

• Approx. Duration: 4 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: Pins PTA1 and PTA0.

• Input Parameters:

— None

• Returns:

— void

3.2.31 UINT8 TPMS_MSG_READ(void)

• Description: This function is in charge to read any incoming message at a network level via an

emulated serial interface on PTA1 and PTA0. As the master, the FXTH87xx11 and FXTH87xx12
manages the clock on P T A1. On falling edge of the clock, the modul e reads a new data bit on P T A0
(programmed as input), MSB first.

• Stack size: 2 bytes

• Approx. Duration: 80 usec.

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: Pins PTA1 and PTA0.

• Input Parameters:

— None

• Returns:

— UINT8 u8ReadByte: Incoming byte from the emulated serial interface.

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3.2.32 UINT8 TPMS_MSG_WRITE(UINT8 u8SendByte)

• Description: This function is in charge to write a message at a network level via an emulated serial

interface on PTA1 and PTA0. As the master, the FXTH87xx11 and FXTH87xx12 manages the
clock on PTA1. On rising edge of the clock, the module puts down a new data bit on PTA0
(programmed as output), MSB first.

• Stack size: 2 bytes

• Approx. Duration: 80 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: Pins PTA1 and PTA0.

• Input Parameters:

— UINT8 u8SendByte: Byte to be outputted through the emulated serial interface.

• Returns:

— UINT8 u8ReadByte: Incoming byte from the emulated serial interface.

3.2.33 UINT8 TPMS_CHECKSUM_XOR(UINT8 *u8Buffer, UINT8 u8Size, UINT8 u8Checksum)

• Description: Calculates a checksum for the given buffer based on XOR operations.

• Stack size: 5 bytes

• Approx. Duration: 80 usec for 8 bytes of data.

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: N/A

• Input Parameters:

— UINT8 *u8Buffer: Buffer where data is located.
— UINT8 u8Size: Size of buffer (in bytes).
— UINT8 u8Checksum: Previous checksum. This argument is useful when the function is used

recursively. It must equal “0” if there is no previous data.

• Returns:

— UINT8 u8NewChecksum: New calculated checksum.

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3.2.34 UINT8 TPMS_CRC8(UINT8 *u8Buffer, UINT16 u16SizeInBytes, UINT8 u8Remainder)

• Description: Calculates a CRC8 on a portion of the designated area using polynomial x^8 + x^5

+ x^3 + x^2 + x + 1.

• Stack size: 9 bytes

• Approx. Duration: 240 usec for 8 bytes of data.

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: N/A

• Input Parameters:

— UINT8 *u8Buffer: Buffer where data is located.
— UINT16 u16SizeInBytes: Size of the designated buffer (in bytes).
— UINT8 u8Remainder: Initial remainder. This argument is useful when the function is used

recursively. It must equal “0” if there is no previous data.

• Returns:

— UINT8 u8NewCRC: New calculated CRC8.

3.2.35 UINT16 TPMS_CRC16(UINT8 *u8Buffer, UINT16 u16MByteSize, UINT16 u16Remainder)

• Description: Calculates a CRC16 on a portion of the designated memory area by using a look-up

table. Polynomial used is $1021 (standard for CRC16-CCITT).

• Stack size: 13 bytes

• Approx. Duration: 226 usec for 8 bytes.

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: N/A

• Input Parameters:

— UINT8 *u8Buffer: Buffer where data is located.
— UINT16 u16MByteSize: Size of the designated buffer (in bytes)
— UINT16 u16Remainder: Initial remainder.

• Returns:

— UINT16 u16NewCRC: New calculated CRC16.

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3.2.36 UINT16 TPMS_SQUARE_ROOT(UINT16 u16Process)

• Description: Calculates a two-digit remainder of (square root * 10) using a fast algorithm.

• Stack size: 49 bytes

• Approx. Duration: 365 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: N/A

• Input Parameters:

— UINT16 u16Process: The number from which to get the square root from.

• Returns:

— UINT16 Root of the number * 10.

3.2.37 void TPMS_READ_ID(UINT8 *u8Code)

• Description: Copies the device’s UniqueID and firmware version stored in firmware flash to

RAM.

• Stack size: 2 bytes

• Approx. Duration: 32 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: N/A

• Input Parameters:

— UINT8 *u8Code: RAM location where data will be copied. Table 26 describes the format of

the 6-bytes returned.

Table 26. u8Code format

Index Description

0 Firmware version.

1 Derivative descriptor.

2:5 32-bit UniqueID.

• Returns:

— void

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3.2.38 void TPMS_LF_ENABLE(UINT8 u8Switch)

• Description: Enables/disables the LFR module.

• Stack size: 5 bytes

• Approx. Duration: 32 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: LFR

• Input Parameters:

— UINT8 u8Switch: Enable (non-zero) or disable (zero) LFR.

• Returns:

— void

3.2.39 UINT8 TPMS_LF_READ_DATA(UINT8 *u8Buffer, UINT8 u8Count)

• Description: Once the user has configured and enabled the LFR, it is customary to go into a

low-power state mode and wait for a datagram. After the first byte of an incoming datagram is
successfully received, this function should be called immediately; It will receive the complete
datagram and place it in RAM. This function assumes that the LFR module is configured
accordingly for a Manchester reception; that the module’s interrupts are enabled; and that the first
byte has already been received and is waiting in the LFR received buffer. While waiting for the
next byte, this function goes into STOP4. If the byte, for an unexpected reason, is not received, this
function has a built-in time-out: After five continuous non-LFR interrupts, the function will assume
a failed LFR reception and exit.

• Stack size: 7 bytes

• Approx. Duration: Data dependant; ~2 msec per byte.

• 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 LFR interrupt to wake-up from STOP mode. It

does not await any other interrupts and should not be affected by them.

• Resources: LFR

• Input Parameters:

— UINT8 *u8Buffer: RAM Buffer where data will be placed.
— UINT8 u8Count: Number of bytes expected.

• Returns:

— UINT8 u8BytesReceived: Actual number of bytes received.

WARNING

This function requires ~24 usec from the moment it is called to the moment
the first byte is copied into the RAM buffer . The user must consider this time
when designing their firmware.

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3.2.40 UINT8 TPMS_WIRE_AND_ADC_CHECK(UINT8 u8TestMask)

• Description: This function will check if there is any bonding wire failure between the embedded

core and the P-cell; or between the core and the g-cell. It will also perform an optional a g-cell
self-test, and/or an ADC test. The latter will consist on taking two reference measurements (ground
and Vdd) using internal channels and comparing them with the expected results. The optional
g-cell self-test sends a self-test signal and verifies that the g-cell deflects as expected. It can only
be called when the device is in parking or static mode. When configuring for a P-cell or g-cell wire
check, Interrupts must be enabled before calling this routine. In case of no issues found, “0” will
be returned, else it will set status flags as follows:

— On P-cell wire-bond error, sets “pressure error” flag.
— On g-cell wire-bond or Self-Test error, sets “acceleration error” flag.
— On ADC error, sets the “ADCERR” flag.

• Stack size: 36 bytes

• Approx. Duration: 14,926 usec (all checks), 106 usec (ADC only), 3,089 usec (P-cell only),

3,087 usec (X-Axis l wire-bond only), 3,089 usec (Z-Axis 1 wire-bond only), 5622 usec (g-cell
Self-Test only).

• 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: ADC, SMI, internal bond wires.

• Input Parameters:

— UINT8 u8TestMask: This variable determines what checks are performed as described by

Table 27.

Table 27. u8TestMask format

u8TestMask Bit Description

BIT0 Reserved.

BIT1 If set, g-cell Self-test performed. Refer to warning below.

BIT2 If set, P-cell bond-wire check performed.

BIT3 If set, X-axis bond-wire check performed.

BIT4 If set, Z-axis bond-wire check performed.

BIT5:6 Reserved.

BIT7 If set, ADC check performed.

• Returns:

— UINT8 u8Status: Status flags as described in Table 28.

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Table 28. u8Status valid values for TPMS_WIRE_AND_ADC_CHECK

u8TestMask Bit Description

BIT0:1 Always clear.

BIT2 If set, P-cell bond-wire error detected.

BIT3 If set, X-axis bond-wire error detected.

BIT4 If set, Z-axis bond-wire or Self-Test error detected.

BIT5:6 Always clear.

BIT7 If set, ADC error detected.

WARNING

The Self-T est option will only return valid readings when the device is static
(i.e. the vehicle is not moving). It is the user’s responsibility to ensure it is
only called while in parking or static mode.

3.2.41 void TPMS_FLASH_WRITE(UINT16 u16Address, UINT8* u8Buffer, UINT8 u8Size)

• Description: This function writes consecutive bytes from a given address in memory to a specified

location in FLASH.

• Stack size: 15 bytes

• Approx. Duration: 1336 usec for 8 bytes of data.

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will be affected by

interrupts.

• Resources: Global RAM locations $0090 - $00CA.

• Input Parameters:

— UINT16 u16Address: Flash starting address.
— UINT8 *u8Buffer: Source memory address.
— UINT8 u8Size: Number of data bytes to be written.

• Returns:

— void

WARNING

This routine will overwrite the contents of RAM locations $0090 - $00CA.

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3.2.42 UINT16 TPMS_FLASH_CHECK(void)

• Description: This function calculates the CRC16 checksum for the Freescale firmware area

(addresses $E000 - FF AD) using the function TPMS_CRC16. It compares it with a pre-calculated
stored value and reports if these two values match or not.

• Stack size: 17 bytes

• Approx. Duration: 214070 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: N/A

• Input Parameters:

— None.

• Returns:

— UINT16 u16Status: “0” in case the calculated checksum and the stored one are the same, or the

calculated checksum in case they are different.

3.2.43 UINT8 TPMS_FLASH_ERASE(UINT16 u16Address)

• Description: This function erases 1 page (512 bytes) of flash at a time.

• Stack size: 11 bytes

• Approx. Duration: 22744 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It may be affected by

interrupts.

• Resources: Global RAM locations $0090 - $00CA.

• Input Parameters:

— UINT16 u16Address: any given address. The whole page where this address resides will be

erased (i.e. if u16Address = $D234, the contents of addresses $D200 - $D3FF will be erased).

• Returns:

— Zero if the page was erased successfully; else, one.

WARNING

This routine will overwrite the contents of RAM locations $0090- $00CA.

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3.2.44 UINT8 TPMS_FLASH_PROTECTION(UINT8 u8Range, UINT16 u16Key)

• Description: This function enables flash protection for a custom memory block. After its

execution, both TPMS_FLASH_WRITE and TPMS_FLASH_ERASE will be unable to perform
any operation in the protected blocks, but shall be operational in unprotected areas.

• Stack size: 11 bytes

• Approx. Duration: 736 usec if protecting; 20.4 usec for a failed attempt.

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will be affected by

interrupts.

• Resources: Global RAM locations $0090 - $00CA.

• Input Parameters:

— UINT8 u8Range: Byte determining the first address of protection, using the Freescale FPROT

convention. Refer to product spec for a description of this register.

— UINT16 u16Key: Due to the irreversible status after the execution of this routine, this argument

is used as a fail-safe to guarantee desired execution of the function. Only when u16Key is equal
to the least-significant word of the UniqueID will this function execute successfully.

• Returns: UINT8 u8Status: according to table below.

Table 29. Possible status values for TPMS_FLASH_PROTECTION

Return Value Description

$0 u16Key matches lower 16-bits of UniqueID; protection was disabled and now is enabled.

$1 u16Key does not match lower 16-bits of UniqueID; protection was disabled and continues to be so.

$2 u16Key matches lower 16-bits of UniqueID; protection was already enabled.

$3 u16Key does not match lower 16-bits of UniqueID; protection was already enabled.

$4

$5 - $FF Reserved.

u16Key matches lower 16-bits of UniqueID; protection was disabled and continues to be so (Failed
writing protection).

WARNING

This routine can only be executed once. After successful execution of this
routine, TPMS_FLASH_WRITE and TPMS_FLASH_ERASE will be
permanently disabled.

FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide, Re v. 2.1

42 Freescale Semiconductor, Inc.

Firmware Functions

u16NewAverage u16POld u8AVG 1–u8PNew+u8Avg=

3.2.45 void TPMS_MULT_SIGN_INT16(INT16 i16Mult1, INT16 i16Mult2, INT32* pi32Result)

• Description: This function will multiply two signed 16-bit numbers together.

• Stack size: 17 bytes

• Approx. Duration: 60 usec

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It should not be affected by

interrupts.

• Resources: N/A

• Input Parameters:

— INT16 i16Mult1: First multiplier .
— INT16 i16Mult2: Second multiplier .
— INT32* pi32Result: Pointer to a 32-bit variable where the result will be stored.

• Returns:

— void

3.2.46 UINT16 TPMS_WAVG(UINT8 u8PNew, UINT16 u16POld, UINT8 u8Avg)

• Description: This subroutine calculates a new weighed average value for a given new and old

measurement readings by using the following equation:

• Stack size: 12 bytes

• Approx. Duration: 38 usec (average of 2), 43 usec (average of 4), 48 usec (average of 8), 53 usec

(average of 16), 56 usec (average of 32).

• Power Management: This function executes entirely in RUN mode.

• Interrupt Management: This function does not await any interrupts. It will not be affected by

interrupts.

• Resources: N/A

• Input Parameters:

— UINT8 u8PNew: new value to include in average.
— UINT16 u16Pold: Old average.
— UINT8 u8Avg: Weight of the average. This value can be 2, 4, 8, 16, 32; any other value will

return an incorrect response.

• Returns:

Eqn. 1

Freescale Semiconductor, Inc. 43

— UINT16 u8NewAverage: resulting weighed average of both old average and the new value

(refer to Example 1).

FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide, Re v. 2.1

Firmware Functions

3.2.47 void TPMS_RDE_ADJUST_PRESSURE(UINT16* pu16UUMA, T_RDE* ptRDEValues)

• Description: This routine’s functionality has been removed, but its prototype is still callable for

backward compatibility. It always returns CLEAR, and doesn’t affect any passed argument.

• Stack size: 4 bytes.

• Approx. Duration: 9 usec.

• Power Management: Interrupt Management: This function does not await any interrupts. It

should not be affected by interrupts.

• Resources: Core

• Input Parameters:

— UINT16 *pu16UUMA: Pointer to Universal Uncompensated Measurement Array (as

described in Section 2.3). No values are affected.

— T_RDE* ptRDEValues: Pointer to an array of elements. For more information on the RDE

structure, refer to Section 2.5.

• Returns: UINT8 u8Status:Always CLEAR.

FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide, Re v. 2.1

44 Freescale Semiconductor, Inc.

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Document Number: FXTH87XX1XFWUG
Rev. 2.1
10/2014