FXTH87E
FXTH87E, Family of Tire Pressure Monitor Sensors
Rev. 4.0 — 29 November 2018
Reference manual
1
About this document
1.1 Purpose
This reference manual describes the features, architecture, and programming model of
the FXTH87E family of devices.
1.2 Audience
This document is primarily for system architects and software application developers who
are using or considering use of the FXTH87E in a system.
1.3 Related documentation
The FXTH87E device features and operations are described in a variety of reference
manuals, user guides, and application notes. To find the most-current versions of these
documents:
1. Go to the FXTH87E page on NXP.com at:
http://www.nxp.com/FXTH87E
2. Select the documentation tab and review the related documentation.
Contact NXP sales representatives for performance attributes such as electrical,
mechanical, and time-based characteristics.
2
Product profile
2.1 General description
The FXTH87E is a small (7 x 7 mm), fully integrated tire pressure monitoring sensor
(TPMS). It also provides low transmitting power consumption, large customer memory
size and dual-axis accelerometer architecture. The FXTH87E TPMS solution integrates
an 8-bit microcontroller (MCU), pressure sensor, XZ-axis or Z-axis accelerometer and RF
transmitter.
2.2 Features and benefits
•
•
•
•
•
•
•
•
Long battery service life
Provided software for power optimization
Pin for pin electrical connections compatible with FXTH87-based customer applications
Included firmware subroutines compatible with FXTH87-based customer software
Pressure sensor with one of three calibrated pressure ranges
Temperature sensor
Optional XZ- or Z-axis accelerometer with adjustable offset option
Voltage reference measured by ADC10
NXP Semiconductors
FXTH87E, Family of Tire Pressure Monitor Sensors
•
Six-channel, 10-bit analog-to-digital converter (ADC10) with two external
I/O inputs
•
8-bit MCU
–
S08 Core with SIM and interrupt
–
512 RAM
–
16 KB FLASH
–
64-byte, low-power, parameter registers
•
Dedicated state machines to sequence routine measurement and transmission
processes for reduced power consumption
•
Internal 315-/434-MHz RF transmitter
–
External crystal oscillator
–
PLL-based output with fractional-n divider
–
OOK and FSK modulation capability
–
Programmable data rate generator
–
Manchester, Bi-Phase or NRZ data encoding
–
256-bit RF data buffer variable length interrupt
–
Direct access to RF transmitter from MCU for unique formats
–
Low-power consumption
•
Differential input LF detector/decoder on independent signal pins
•
Seven multipurpose GPIO pins
–
Four pins can be connected to optional internal pullups/pulldowns and STOP4
wakeup interrupt
–
Two of seven pins can be connected to a channel on the ADC10
–
Two of seven pins can be connected to a channel on the TPM1
•
Real-time Interrupt driven by LFO with interrupt intervals of 2, 4, 8, 16, 32, 64, or 128
ms
•
Free-running counter, low-power, wakeup timer and periodic reset driven by LFO
•
Watchdog timeout with selectable times and clock sources
•
Two-channel general purpose timer/PWM module (TPM1)
•
Internal oscillators
–
MCU bus clock of 0.5, 1, 2, and 4 MHz (1, 2, 4, and 8 MHz HFO)
–
Low frequency, low power time clock (LFO) with 1 ms period
–
Medium frequency, controller clock (MFO) of 8 μs period
•
Low-voltage detection
•
Normal temperature restart in hardware (over- or under-temperature detected by
software)
FXTH87E
2.3 Configuration options
Table 1. Configuration options
Pressure range
Accelerometer
configuration
Z
100 to 500 kPa
XZ
Z
100 to 900 kPa
XZ
X-axis range
N/A
–80 g to +90 g
NA
–80 g to +90 g
Z-axis range
–285 g to +400 g
–215 g to +305 g
–285 g to +400 g
–285 g to +400 g
–215 g to +305 g
–285 g to +400 g
© NXP B.V. 2018. All rights reserved.
Package
98ASA00432D
(7 x 7 x 2.2 mm)
FXTH87ERM
All information provided in this document is subject to legal disclaimers.
Reference manual
Rev. 4.0 — 29 November 2018
2 / 182
NXP Semiconductors
FXTH87E, Family of Tire Pressure Monitor Sensors
FXTH87E
2.4 Part number definition
a XTH87E b cc d T1
Table 2. Part number breakdown
Code
a
b
Option
P
F
G
H
01
cc
02
11
12
d
Single
digit or
alphabetic
character
Description
a = P (Prototype)
a = F (Qualified)
b = G (500 kPa range)
b = H (900 kPa range)
cc = 01 (Z-axis 300 g range)
cc = 02 (Z-axis 400 g range)
cc = 11 (X-axis 90 g range, Z-axis 300 g range)
cc = 12 (X-axis 90 g range, Z-axis 400 g range)
d = Number or letter marketing suffix (A-Z, a-z or 0-9)
2.5 Part marking definition
a 87E b c d
Table 3. Part marking breakdown
Code
a
b
Option
P
F
G
H
E
c
J
H
M
d
Single
digit or
alphabetic
character
Description
a = P (Prototype)
a = F (Qualified)
b = G (500 kPa range)
b = H (900 kPa range)
c = 01 (Z-axis 300 g range)
c = 02 (Z-axis 400 g range)
c = 11 (X-axis 90 g range, Z-axis 300 g range)
c = 12 (X-axis 90 g range, Z-axis 400 g range)
d = Number or letter marketing suffix (A-Z, a-z or 0-9)
FXTH87ERM
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2018. All rights reserved.
Reference manual
Rev. 4.0 — 29 November 2018
3 / 182
NXP Semiconductors
FXTH87E, Family of Tire Pressure Monitor Sensors
FXTH87E
3
General Information
3.1 Overall block diagram
The block diagram of the FXTH87E is shown in
Figure 1.
This diagram covers all the
main blocks mentioned above and their main signal interactions. Power management
controls and bus control signals are not shown in this block diagram for clarity.
TRANSDUCERS
SENSOR
MEASUREMENT
INTERFACE (SMI)
SMI
P
PRESS
SENSOR
Z
ACCEL
(OPTION)
Z
PWU
TIMER
LFO
1 ms
MCU
LFO
RTI
TIMER
XZ
ACCEL
(OPTION)
XZ
VSENS
OSC
LVD
MCU CORE
S08
BKGD/
PTA4
VDD
AVDD
VDD
AVDD
AVSS
VSS
TEMP
RESTART
TEMP
TEMP
SENSOR
BANDGAP
REF
VTP
ADC10
10-BIT
6-CHAN
V0
MFO
8 s
V
1
VREG
V2
MFO
HFO
1, 2, 4,
or 8 MHZ
64-BYTE
PARAMETER
REGISTER
RAM
MEMORY
512
USER
FLASH
MEMORY
FIRMWARE
MEMORY
TPM1
TIMER/PWM
2-CHAN
AVDD
RESET
VREG
RFVDD
XI
XO
VOLT
REG
DX
XTAL
OSC
BIT
RATE
GEN
RF LVD
LF
RECVR
(LFR)
LFA
LFB
256-BIT
DATA
BUFFER
VCO/PLL
FRACTL
DIVIDER
LFI
DATA
ENCODE
RF CONTROLLER
FREE-RUNNING
COUNTER
RF
RVSS
RF
AMP
KBI
KEYBOARD
WAKEUP
GP
I/O
PTA0
PTA1
PTA2
PTA3
PTB0
PTB1
RFM
aaa-027989
Figure 1. FXTH87E overall block diagram
FXTH87ERM
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© NXP B.V. 2018. All rights reserved.
Reference manual
Rev. 4.0 — 29 November 2018
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NXP Semiconductors
FXTH87E, Family of Tire Pressure Monitor Sensors
FXTH87E
3.2 Multi-chip interface
The FXTH87E contains two to three devices using the best process technology for each.
•
Microcontroller with accelerometer and pressure sensor interfaces, and RF transmitter
(MCU)
•
Optional ranges on pressure transducers
•
Optional XZ- or Z-axis acceleration transducer
As shown in
Figure 1,
the MCU interfaces to the RF transmitter using a standard memory
mapped registers. The transducers connect to the MCU using custom analog interfaces
and inter-chip bonding wires.
3.3 System clock distribution
The various clock sources and their distribution are shown in
Figure 2.
All clock sources
except the low frequency oscillator, LFO, can be turned off by software control in order to
conserve power.
LFO
OSC
1 ms
PERIOD
BUSCLKS[1:0]
ADCCLK
HFO OSC
1, 2, 4,
and 8 MHz
f
OSC
÷2
f
BUS
ADC10
4 kbps
LF
COPCLKS
CPU
WATCH
DOG
BDC
PWU
FRC
÷8
f
MFO
BIT
RATE
GEN
f
XCO
XO
PLL
RF
OUT
VCO
DATA
BUFFER
SENSOR MEASUREMENT
INTERFACE
41.67 kHz
sampling
PRESSURE
SENSOR
41.67 kHz
sampling
X-AXIS
SENSOR
41.67 kHz
sampling
Z-AXIS
SENSOR
RF STATE
MACHINE
MFO
OSC
8 s
LFOSEL
f
MFO
f
LFO
(1 kHz)
TCLKDIV
DX (500 kHz)
f
LFO
(1 kHz)
PTA2
CH0
TPMI
CH1
PTA3
RANDOM
(0 to 1 MHz)
RANDOM
(0 to 1 MHz)
LFR
LFRO
OSCILL
CLSA, CLKSB
(125 kHz)
SYSTEM
CONTROL
LOGIC
RTI
ACD10
CLOCK
ADC10
MCU
RTICLKS
PAR
REG
RAM
FLASH
XTL
OSC
26 MHz
XI
TRANSDUCERS
aaa-027990
Figure 2. Clock distribution
FXTH87ERM
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2018. All rights reserved.
Reference manual
Rev. 4.0 — 29 November 2018
5 / 182
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