TPMS Presentation April 1 2014 - Sr.Auto FAE Alan Yang 杨涛
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TPMS Presentation
April 1 2014
Sr.Auto FAE
Alan Yang (杨涛）
Freescale Confidential Proprietary
TMTPMS 7*7 package Agenda
• Marketing trend
• How does TPMS module work in car
• Detailed specification of MPX87xx
• TPMS road map and comparison with the other supplier
• Our enablement resources
• Q&A
TM
1TM Freescale, the Freescale logo, AltiVec, C-5, CodeTEST, CodeWarrior, ColdFire, C-Ware, t he Energy Efficient Solutions logo, mobileGT, PowerQUICC, QorIQ, StarCore and Symphony are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. BeeKit, BeeStack, ColdFire+, CoreNet, Flexis, Kinetis, MXC, Platform in a Package, Processor Expert, QorIQ Qonverge, Qorivva, QUICC Engine, SMARTMOS, TurboLink, VortiQa and Xtrinsic are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2011 Freescale Semiconductor, Inc.
Tire Pressure motivated by Auto mega trends
Mobility for everyone Cleaner world for everyone
• TPMS is available for all type of • TPMS allows optimum tire
vehicles including truck and inflation and thus fuel
busses consumption and CO2 emission
• Scalable solutions reduction
• Multiple pressure ranges • Maximizes tire life
• Multiple rotation axis • European and Korean legislation
• Multiple RF frequencies driven by CO2 reduction
Safety for everyone Always Connected
• Prevent roadside breakdown and • Provides accurate tire data to the
risk of road congestion driver
• US tread act to prevent roll over • Filling assistant app on smart
accidents phones
• Future possibilities to link tire • Fleets & Truck: enables better tire
information with chassis and management
ADAS system
TM
3TPMS legislation around the world
Region Requirements
USA Regulation from 2005: FMVSS138 mandates TPMS for new vehicles starting
from October 1st 2005
European Union Regulation from 2012: EC661-2009 mandates TPMS starting Nov 2012 for
new type approved vehicles and for all new vehicles starting from Nov 2014:
TPMS will be tested as part of the new EU standardized plan for vehicle
periodical inspection
S. Korea / Japan Regulation from 2013: TPMS vehicles to be installed on passenger cars from
January 2013 for new model and January 2015 for existing model
Russia, Kazakhstan, Valid from 2015 onwards & replaces nation legislation
Belarus (Eurasia)
Indonesia, Israel, Require European whole vehicle type approval for vehicles imported from
Malaysia, Philippines, Europe. As a consequence TPMS will be required for all new vehicles in
Turkey November 2014
China Recommended specification
Enforcement Standard in Preparation
TM
4TPMS potential market size
• 100 Million new cars sold per year by the end of the
decade
−4 wheel per car + spare tires + winter tires
− Module Replacement market
• 1 billion cars on the road worldwide
− Great aftermarket opportunity
− Great potential for tire mounted solutions
• Heavy trucks, busses, motorcycles
• Market outside of transportation requiring battery
operated wireless pressure sensing
TM
5MPXY8700 Packaging
Gcell
Pcell
MCU + RF
QFN 9 x 9 mm
Cavity Package
(Cross Section)
Gel
Selective encapsualtion
Metal cap
Plastic Plastic
housing Gcell housing
Gel Pcell
Plastic flag
Leadframe
Not to scale. For illustration purposes only.
TM
6TM Freescale, the Freescale logo, AltiVec, C-5, CodeTEST, CodeWarrior, ColdFire, C-Ware, t he Energy Efficient Solutions logo, mobileGT, PowerQUICC, QorIQ, StarCore and Symphony are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. BeeKit, BeeStack, ColdFire+, CoreNet, Flexis, Kinetis, MXC, Platform in a Package, Processor Expert, QorIQ Qonverge, Qorivva, QUICC Engine, SMARTMOS, TurboLink, VortiQa and Xtrinsic are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2011 Freescale Semiconductor, Inc.
Tire Performance Issues
Worsening until around 1.5 ba, then improvement due to bell formation of tread
Aquaplaning (water depth >2 mm)
centre inwards (at rated load)
General durability Reduced with lower pressures
A reduction by 0.5 bar results in a worsening of 15 km/h in endurance (e.g.
Test Stand durability
Failure at 185 km/h instead of 200 km/h)
A reduction by 0.5 bar results in damage sustained at 20% lower speed (e.g. at
Resistance to curb impact
40 km/h instead of 50 km/h)
The limit value for unseating of bead from rim lies between the operating
Bead unseating from rim
pressure and 1 to 1.2 bar. For safety reasons, this should never be lower
Wear A tire with 20% lower pressure has a running life around 30% less
Rolling Resistance A reduction by 0.5 bar results in an increase in rolling resistance of around 15%
A deviation of 1 bar from normal pressure (2 to 2.5 bar) worsens the noise level
Tread Noise
by 2 dbA (66%).
On a mid-class car, an air pressure deviation of 0.2 bar from one axle is
Handling on dry and wet surfaces
noticeable.
(Source: Michelin Tires)
TM
8Tire Performance Issues
100
80 108 140
Rolling Resistance (%)
Service Life (%)
60 106 130
Fuel Use (%)
40 104 120
20 102 110
0 101 100
120 110 100 90 80 70 60 50 40 30 2.0 1.7 1.4 1.1
Tire Pressure (% of Specified) Tire Pressure (bars)
Decreased Tire Life with Increased Fuel Use and
Lower Pressure Rolling Resistance with
Lower Pressure
(Source: Continental Tires)
TM
9Pressure Accuracy
• Measurement accuracy target varies with OEM
− Typical accuracies better than 8-10 kPa (1.2 – 1.4 psi)
− Typical resolutions of 1 to 2 kPa (0.15 – 0.30 psi)
• Accuracy over temperature, supply voltage and life of the
tire/system
• Must warn based on the correct Cold Inflation Pressure (CIP)
specified for the vehicle
• CIP limits usually set in the chassis receiver for a specific
vehicle
TM
10Pressure Accuracy
• Effects of absolute vs. gauge pressure at altitude
− In tire sensors measure absolute pressure
− Typical tire gages measure differential (gauge) pressure
relative to the atmosphere
• CIP is defined as the pressure of the tires after
the has been stopped for at least 1 hour
• The “corrected” pressure using the Ideal Gas Law
is not used
− It is not the mass of air present setting tire performance
− It is pressure of the air that defines the load carrying capability and
performance of the tire
• Generally accepted to use absolute pressure with a fixed
atmospheric offset (approx 100 kPa = 14.5 psi)
TM
11TPMS System Solutions
• Direct (Measure Pressure in the Tire)
− Useabsolute pressure sensor inside the tire volume
− Communication via LF and/or RF links
− Mounted inside the tire/wheel
On the wheel (valve stem or drop center)
On the tire (side wall, bead area or tread belt)
− Powered by energy source
Internal
battery
Source other than battery (battery-less)
• Indirect (Measuring Some Other Parameter)
− Infer under-inflation by using parameter other than pressure sensing
Wheel speed variations
Ride height variations
Tire vibration variations
− No power source required on the wheel/tire
TM
12Tire Pressure Monitor Systems: Indirect Measuring
• Implemented through ABS wheel
speed sensors
• ABS system is able to measure
individual wheel speed and
compare it against other wheels
• If a wheel is moving faster, it is
very likely it is under-inflated
≠
http://www.aa1car.com/library/diagnosing_abs_wheels_speed_sensors.htm
TM
13Tire Pressure Monitor Systems: Direct vs. Indirect
Direct Indirect
Precision ☺
Reaction time ☺
Detection of multiple ☺
faults
Position-dependant ☺
pressure warning
Robustness under ☺
different driving
conditions
Number of additional ☺
components
System cost ☺
Required driver ☺
interaction
Additional comfort ☺
features
TM
14Tire Pressure Monitor Systems: Indirect Measuring
Like
• Hardware reuse (ABS system)
• Cheap
Don’t like
• Measurement relative to other tires
• Can only sense
• One under-inflated tire
• Three tires are under-inflated
• Two diagonally-positioned tires are under-inflated
• Will not work with under-inflated tires
• 2 on the same axle
• 2 on the same car side
• All 4
TM
15Direct TPMS Mounting Methods
Tire Wall Tire Tread Mount
Valve Stem Mount Drop Well Mount
TM
16TPMS Architectures
• Other Direct TPMS system features in the marketplace
− Display actual individual tire pressures
− “Tire Localization”
determine location of tire on car
− “Auto-Learn”
determine tire IDs on the car
− “Initiation”
triggering a pressure reading on demand
− Motion detection to change monitoring rates
− Motion detection to save battery power when parked
− Diagnostics for manufacturing and field service
TM
17Sensor Package Comparison
Competitor Freescale Freescale
MPXY85XX MPXY87XX
/MPXY86XX
• PG-DSOSP-14-6
• 9.24 X 11.09 X 3.9 mm
MPXY85xx/86xx smaller in size will • QFN 9x9x2.3mm
help on module’s size, weight and cost.
TM
18
18Top Level TPMS Model
Coil
LF LF
3V Motion
Receiver Signal
Batt Sensor
RF
Pressure Energy
Ant
Sensor
Controller RF
Transmitter
Temp
Sensor
TM
19Tire Pressure Monitoring Body Receiver
Stand along TPMS display
Cluster
Infotainment
Antenna
RF
Receiver
MCU & LF
General
Control 24 psi Systems
Stand along TPMS receiver
Or RKE System Basic
MIL
Or PKE System Systems
TM
20TM Freescale, the Freescale logo, AltiVec, C-5, CodeTEST, CodeWarrior, ColdFire, C-Ware, t he Energy Efficient Solutions logo, mobileGT, PowerQUICC, QorIQ, StarCore and Symphony are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. BeeKit, BeeStack, ColdFire+, CoreNet, Flexis, Kinetis, MXC, Platform in a Package, Processor Expert, QorIQ Qonverge, Qorivva, QUICC Engine, SMARTMOS, TurboLink, VortiQa and Xtrinsic are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2011 Freescale Semiconductor, Inc.
FXTH87xxxx6T1 Tire Pressure Monitoring System
16K Flash
LVD BG LFR • Microcontroller
Detect and Decode
Wakeup Timer • S08 core, 0.25um SGF technology
512b TPM • 16 kB SGF flash (8kB firmware, 8kB
OSC 8 MHz
RAM 2-ch customer), 512B RAM, 64 parameter registers
LFO 1 kHz • 10 bit ADC, temperature sensor and thermal
Register 10-bit ADC
64 Bytes Temp Sensor restart
• 1-channel LF detector and decoder
Temp Restart
S08 Core • 8 MHz clock, 2-ch timer, 1 kHz LFO
UHF TX • Integrated RF transmitter
315 / 434 MHz C to V
BDM • Frac-N PLL based transmitter, 315/434 MHz
• FSK/ASK modulation
• Manchester or bi-phase encoding
Pressure Cell XZ-axis Accel
• -1dBm to +8 dBm output power
• Design Considerations: • Pressure Sensor
• CMOS capacitive p-cell w/o signal conditioning
• RF Tx (7mA @ 5 dBm)
• LF Rx (4uA, snif)
• Process Technology – 0.25um
• Core Type – S08
• Voltage Supplies – 1.8V to 3.6V (transmit)
• Acceleration Sensor
• Voltage Supplies – 2.3V to 3.6V (measure) • Single XZ die
• Packaging Requirements – Media protection
• Package
• FAM 7x7mm QFN w/ gel fill
TM
22FXTH87xxxx6T1 Tire Pressure Monitoring System
Integrated Tire Pressure Monitoring System (TPMS) with smallest footprint (7mmx7mm)
lowest power consumption, largest customer memory size (8kB flash, 512byte RAM)
and unique dual-
dual-axis accelerometer architecture
Smallest Package Size Integrated XZ-Accelerometer Robustness / Power
• The compact 7 x 7 mm industry- • Including an XZ-axis • Robust package design with
leading package enables smallest accelerometer offers customers encapsulated inter-chip bond wires
module design for lighter weight motion detection and tire
applications localization capabilities • Storage temp: -50C / +150C
• Same height as QFN 9x9 for • Smallest RF transmit battery
smooth transition to QFN 7x7 consumption
solutions • 8kB of customer flash memory gives
• Highest degree of functional more application flexibility. Possible
integration: interface with external memory if
required
• Dual-axis accel, LF, RF,
Pressure, MCU in one • 512byte RAM
package
TM
23Troubleshooting: Typical Currents at ambient temperature
RF Behavior (To be
Normal Operation added to normal RESET BKGD
operation)
RF
RUN Mode STOP4 STOP1 RF ON Adder
Transmission 1.2 mA 1.2 – 1.5 mA
2 mA 73 uA 0.5uA 77 uA
6mA
TM
24Competitive Positioning & Value Proposition
• Customers cost benefit
− Smaller in size: 7mmx7mmx2.2mm
− Saving on board size , potting and housing materials.
− Saving on module weight (car OEM requirement)
− Boot Loader design allow uploading SW through LF – reduce cost of car OEMs
call back cost by uploading SW at site.
− Auto-localization by using dual axis accelerometers.
• Longer battery life
− 35% RF transmitting power consumption.Lausitz: Significant Requirements - General
Characteristic Description
Data Interfaces
Low Frequency Receiver
Frequency 125 kHz
Modulation ASK
Carrier Sensitivity Ranges 70 / 10, 14 / 2, & 3 / 0.5 mV ( Det / No Det
Data Sensitivity Ranges 14 / 2 & 2.5 / 0.25 mV ( Det / No Det )
RF Transmitter
Frequency 315 , 434 MHz
Modulation ASK, FSK
Transmit Power 5 dBm, 8dBm
Package 7 x 7 mm 24 –Pin QFN
Physical Architecture – MCU HSC08 - SZK16 dedicated MCU
Physical Architecture – Pressure Transducer Capacitive cell with 100 up to 900 kPa range
Temperature sensor ∆VB sensor with -40 to +125°C range
Voltage Sensor Internal bandgap voltage reference
Physical Architecture – Z-Axis Transducer Teeter Totter Element
X-Axis Transducer X-lateral Element
TM
26Lausitz and Nogaro Portfolio Under Development
Operating Temp P-cell range Axis of
Logical part number Device name (QFN 7x7) X-range Z-range
range (kPa) accel
Nogaro FXTH8705026T1 -40C / + 125 C 100-450 Z NA -270g /+ 350g range with 40g sens
Nogaro FXTH870502DT1 -40C / + 125 C 100-450 Z NA -270g /+ 350g range with 40g sens
Lausitz FXTH8705116T1 -40C / + 125 C 100-450 XZ -70g/+80g range with 10g sens -210g/+240g range with 60g sens
Lausitz FXTH870511DT1 -40C / + 125 C 100-450 XZ -70g/+80g range with 10g sens -210g/+240g range with 60g sens
Nogaro FXTH8709026T1 -40C / + 125 C 100-900 Z NA -270g /+ 350g range with 40g sens
Nogaro FXTH870902DT1 -40C / + 125 C 100-900 Z NA -270g /+ 350g range with 40g sens
Lausitz FXTH8709116T1 -40C / + 125 C 100-900 XZ -70g/+80g range with 10g sens -210g/+240g range with 60g sens
Lausitz FXTH870911DT1 -40C / + 125 C 100-900 XZ -70g/+80g range with 10g sens -210g/+240g range with 60g sens
Lausitz FXTH8709126T1 -40C / + 125 C 100-900 XZ -70g/+80g range with 10g sens -270g /+ 350g range with 40g sens
Lausitz FXTH870912DT1 -40C / + 125 C 100-900 XZ -70g/+80g range with 10g sens -270g /+ 350g range with 40g sens
TM
27TM Freescale, the Freescale logo, AltiVec, C-5, CodeTEST, CodeWarrior, ColdFire, C-Ware, t he Energy Efficient Solutions logo, mobileGT, PowerQUICC, QorIQ, StarCore and Symphony are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. BeeKit, BeeStack, ColdFire+, CoreNet, Flexis, Kinetis, MXC, Platform in a Package, Processor Expert, QorIQ Qonverge, Qorivva, QUICC Engine, SMARTMOS, TurboLink, VortiQa and Xtrinsic are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2011 Freescale Semiconductor, Inc.
TPMS Roadmap
Tire Pressure
Monitoring
Nogaro Z-axis
Z axis
450/900 kPa
0.25uSGF, 2-Poly,
2 Poly, 7x7 FAM
MPXY85xx - Z-axis
450/900 kPa
0.25uSGF, 2-Poly, 9x9 Cav QFN C90FGUHV IP Blocks U-TPMS XZ-axis
450/900/1500 kPa
UMEMS Phs 4P C90FGUHV, UMEMS-4P,
UMEMS 4P, 5x5 FAM or CSP
Lausitz XZ-axis
axis
450/900 kPa
0.25uSGF, 2-Poly,
2 Poly, 7x7 FAM
Proposal
MPXY86xx - XZ-axis
450/900 kPa Lausitz XZ-axis
axis Planning
0.25uSGF, 2-Poly, 9x9 Cav QFN
Up tp 1500 kPa
0.25uSGF, 2-Poly,
2 Poly, 7x7 FAM Execution
Production
Left Edge :
First Sample Date
Right Edge :
Product Qualification
Not resourced
1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q
2013 2014 2015 2016
Preliminary schedule. To be updated by August 31, 2013
TM
29Tire Pressure Monitor Sensor Roadmap Change-points
Gen2 Gen3 Gen4 Gen5
Package SOIC-20 Introduce Introduce Film-Assist Eliminate Die-to-Die
Bottom-side cavity; QFN 9x9, Open top- Mold QFN 7x7 Bond wires;
4-die side cavity; 3-die 2-die
3-die
ASIC Node TSMC 250nm SGF TSMC 250nm SGF TSMC 250nm SGF Introduce 90nm TFS
ASIC Design Dedicated pressure & Muxed C-V signal Muxed C-V signal Battery-less power
inertia interfaces chains w/ Σ∆ ADC, chains w/ Σ∆ ADC, System ID, extended
( A/D & C/V ) digital filters; digital filters; BIST, & selectable
Up-integrate RF Tx Optimized LF/RF sensitivities
MEMS Nodes 2-poly inertia, 2-poly inertia & p-cell 2-poly inertia & p-cell Introduce eHARMEMS
PIDR73 pressure for pressure,
eHARMEMS inertia
MEMS Design X-lat & teeter-totter; X-lat & teeter-totter; X-lat & teeter-totter; Combined Self Test +
Redundant p-chip w/ Redundant p-cell Redundant p-cell Sense
Integrated C-V
Test Physical @ probe & Physical @ probe & Physical / Electrostatic Electrostatic @ probe
final final @ probe & final & final
Certification &/or AEC-Q100 AEC-Q100 AEC-Q100 AEC-Q100
Assessment ASIL-QM, B target
TM
30Competitive Positioning & Value Proposition
• Smaller in size:
− Saving on board size (customer cost benefit)
− Saving on potting material (customer cost
benefit)
− Saving on module weight (car OEM
requirement)
• Flash 8k space for customers
− 33% more space enabling a module suitable
for more car models. (inventory/operation/
production management benefit).
• Unique with dual-axis accelerometer
− enabling tire location determination without
the need for user intervention and/or the use
of LF initiator(s).
• Lower RF transmitting power
consumption
−Power Consumption Comparison
Freescale
Competitor
MPXY8XXX
Operating Voltage
1.9V to 3.6V 1.8V to 3.6V
MCU, RF Transmitter
Operating Voltage
2.1V to 3.6V 2.3V to 3.6V
Measurement
Stop Idd@ 25 °C 0.7 uA 0.7 uA
RF Output 5dBm @315MHz 3V 10 mAMCU Core Comparison
Freescale
Competitor
MPXY8XXX
MCU Core 8051 9S08
Flash for Customer 6K 8K
RAM 256 Byte 512 Byte
MPXY85xx/86xx with 8k flash for customers will allow one module for
more car models by offering 33% more space for customers’ software.
Benefit for customers’ inventory/production/operation management.
TM
33Sensor Performance Comparison
Freescale
Competitor
MPXY8XXX
± 7 kPa ± 7 kPa
0 ℃ to 50 ℃ 0 ℃ to 70 ℃
Low Pressure Range
± 9 kPa ± 10.5 kPa
100-450 kPa
0℃ to 70 ℃ -20 ℃ to 85 ℃
Maximum error
± 17.5 kPa ± 16.8 kPa
-40 ℃ to 125 ℃ -40 ℃ to125 ℃
±10 kPa
0 ℃ to 70 ℃
Medium Pressure Range
± 15 kPa
100-900 kPa
-20 ℃ to 85 ℃
Maximum error
±24 kPa
-40 ℃ to 125 ℃
Z-axis
Accelerometer Only Z-axis XZ-axis
No Accel
MPXY85xx/MPXY86xx offer better temp performance enable
better system accuracy.
TM
34Sensor Performance Comparison (continued)
Freescale
Competitor
MPXY8XXX
Max Operating Temperature -40 ℃ to 125 ℃ -40 ℃ to 125 ℃
±3 ℃ ±3 ℃
(-20 ℃ to 70 ℃) (-35 ℃ to 70 ℃)
Temperature Error
±5 ℃ ±5 ℃
(-40 ℃ to 125 ℃)
℃ ( -40 ℃ to 125 ℃)
℃
Voltage Range 1.9V to 3.6V 1.8V to 3.6V
±100 mV ±75 mV
Voltage Error
(-40 ℃ to 125 ℃) (-40 ℃ to 125 ℃)
TM
35
35Sensor Package Comparison
Competitor Freescale Freescale
MPXY85XX MPXY87XX
/MPXY86XX
• PG-DSOSP-14-6
• 9.24 X 11.09 X 3.9 mm
MPXY85xx/86xx smaller in size will • QFN 9x9x2.3mm
help on module’s size, weight and cost.
TM
36
36RF Basics
The transmitter generates a radio frequency (RF) signal
− OOK : The signal is canceled during low level
− FSK : The frequency of the wave varies with the value of the modulating signal
The transmitter matching network optimize the transfer of power until the antenna
The transmitter antenna transforms this RF signal to an electromagnetic wave
The wave propagates to the receiver’s antenna
The receiver antenna collects the wave at RF frequency
The receiver matching network optimizes the transfer of power until the receiver
input
The receiver processes the signal
Either OOK
Transmit Receive
modulation
Transmitter Matching Matching Receiver
Network Network
Or FSK
modulation
TM
37
• 37RF of TPMS
What is impact RF receiving rate?
RF Receiver design (RF antenna gain, device sensitivity, RF
antenna matching, position & direction on car )
RF emitter design (RF antenna gain, RF power, RF antenna
matching, direction)
RF protocol (FSK or ASK? Repeat times?)
RF Receiving Rate Power consumption Comment
FSK ☺ FSK is less susceptible to
interference
OOK ☺ Lower cost for RF Receiver
side and emitter side
(Shrader)
Lower Baud Rate ☺ It need to repeat the RF
frame when the receiving
Higher Baud Rate rate can’t meet the target.
☺
Shorter Length of ☺ ☺
Protocol
Higher RF power ☺ It need to repeat the RF
frame when the receiving
rate can’t meet the target.
TM
38RF of TPMS
RF Frame Format
TM
39RF Data Encoding
Manchester encoding (most customer)
Customize encoding (S&T, TTE and etc.) NRZ encoding to resolve it!
Bi-phase encoding
TM
40Inter-Frame Spacing of RF
To avoid frame collisions between data from multiple sensors
TM
41TPMS MCU power modes
Variable RUN STOP4 STOP1
Active clocks HFO, MFO, LFO
MFO, LFO
LFO
RAM (512 bytes) Active Stand-by Off
PARAM (64 Active Active Active
bytes)
RF Transmitter Optionally On Optionally On Optionally On
LF Receiver Optionally On Optionally On Optionally On
Sensors Optionally On Optionally On Off
MCU On and clocking Stand-by, not Off
clocking
PWU ON ON ON
GPIOs ON Levels Hi-Z
maintained
Interrupts Optionally ON Optionally ON Some On, Some
off, will start code
from main()
TM
42单向)
单向
Direct TPMS Architecture (单向
RSM RSM
TPMS RF RSM
Receiver
SPARE
RSM RSM
RSM: Remote Sensing Module
TM
43双向)
双向
Direct TPMS Architecture (双向
RSM RSM
LF LF
TPMS RF RSM
Receiver
SPARE
LF
CAN
LF
RSM RSM
RSM: Remote Sensing Module
LF: LF Initiator
TM
44LF in TPMS System
LF emitter in car OEM production line LF emitter in aftermarket
Automatic
product line
Handheld tool
Handheld tool
TM
45Difference of LF Tool
LF on car (Dual way) Automatic product Handheld LF emitter LF in bootloader
Line
Trigger TPMS module •Diagnostic (pressure, •Car model matching, • Programming for
Switch the state accel, battery, state) tire position different car
(stationary, rolling, and record (ID, car •Diagnostic model
localization) module, date) (pressure, accel, •Upgrade code
battery, state) and
record (ID, car
module, date)
40 – 90 cm ? 10 - 50 cm About 10 cm
Above 150 cm is not Above 150 cm is not Above 100 cm is not Above 30 cm is
allowed allowed allowed not allowed
TM
46LF Receiver
Carrier Mode
• Amplitude
• frequency
• duration
Data Mode
• Carrier Mode + Datagram in Manchester format
Direct Mode
• Data Mode with no Manchester decoding
• Used in rare cases
TM
47LF Protocol
Standard LF telegram Manchester code (New TPMS system)
SYNC patterns
Special LF telegram (TPMS for replacement)
200 +/- 20 ms
20 +/- 2 ms 10 +/- 1 ms
TM
48Typical TPM Operational Parameters
Parameter Value Units
Data Measurement Interval
Motion 3 sec
Parked 15 minute
Data Transmission Interval
Motion 60 sec
Parked 60 minute
RF Transmission Protocol
Bit Rate 9600 bits/sec
Bits/Frame 90 bits
Frames/Datagram 4 frames
Pressure Change Alert 256 frames
Diagnostic Modes 6 modes
Pressure Change Alert 15 kPa
Pressure Measure Range 100 to 900 kPa
Temperature Measure Range -40 to +125 °C
TM
49Example TPM Operational Profile
10 Years (87600 hrs)
25000 km/yr Moving (3650 hrs)
4%
decaying 1500 km/yr
Total Distance
182500 km
Average Speed of
50 km/hr
96%
Parked (83950 hrs)
Total Time Moving
3650 hrs Assume Constant
Temperature and Voltage
TM
50Battery life and Power Consumption
Self Discharge
18% Standby
Reserve 35%
10%
16% 21%
Transmit Processing
Assume 250 mA-hr Battery
205 mA-hr used (including self-discharge)
TM
51TM Freescale, the Freescale logo, AltiVec, C-5, CodeTEST, CodeWarrior, ColdFire, C-Ware, t he Energy Efficient Solutions logo, mobileGT, PowerQUICC, QorIQ, StarCore and Symphony are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. BeeKit, BeeStack, ColdFire+, CoreNet, Flexis, Kinetis, MXC, Platform in a Package, Processor Expert, QorIQ Qonverge, Qorivva, QUICC Engine, SMARTMOS, TurboLink, VortiQa and Xtrinsic are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2011 Freescale Semiconductor, Inc.
MPXY87XX/86XX/85XX
Element Used for… Provided by MPXY8XXX
Absolute Pressure Sensor Acquiring tire pressure
Acceleration Sensor(s) Determining if the vehicle is
moving
deciding which wheel it is
(MPXY86XX)
Battery Providing power to the
system
Timer Deciding when to transmit
Control Unit (MCU) Gluing all actions together
RF Transmitter Sending data to the vehicle
LF Receiver Getting instructions from the
outside world
Plastic/Metal housing Holding everything together
“Putting” Isolating electronic
components from tire “goo”
Algorithm Perform actions
systematically
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53Literature
• Data Sheet
− Describes
Silicon
− FXTH87xxxx_rev0 3.pdf
• User Guide
− Describes Firmware
− FXTH87xx11_ug_213.pdf (2-axes
products)
− ngo_ug_294.pdf (1-axis products)
• Reference Manual/Application notes
− AN4277: Interfacing to firmware
− AN4391: LF design considerations
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54MPXY87XX/86XX/85XX : Freescale Firmware
• Physically, one 16Kbyte Flash block
• First half is empty
− 8kbyte for user
• Second half contains Freescale firmware
− Low-level drivers
− Math functions
− Individual Trim/compensation
− UniqueID
− CRC
− Interrupt vectors
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55MPXY87XX/86XX/85XX : Calling Freescale Firmware (1)
• MPXY87XX/86XX/85XX User Guide
contains documentation for all in-flash
firmware routines
• All routines can be called through an
absolute-address pointer
Absolute Address Return Type Function
$E000 Void TPMS_RESET
$E003 UINT8 TPMS_READ_VOLTAGE
$E006 UINT8 TPMS_COMP_VOLTAGE
$E009 UINT8 TPMS_READ_TEMP
$E00C UINT8 TPMS_COMP_TEMP
… … Refer to User Guide for complete
list
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56MPXY87XX/86XX/85XX : Calling Freescale Firmware (2)
• The User Guide also contains a function definition
− For example,
UINT8 TPMS_READ_VOLTAGE(UINT16 *u16UUMA)
• Pointers to absolute addresses casted as pointers to functions can
be declared for each firmware function
− For example,
− #define TPMS_READ_VOLTAGE ((uint8_t(*)(uint16_t*))((uint16_t)0xE003))
• Each pointer can then be treated as a regular C function
− For example,
u8Status = TPMS_READ_VOLTAGE(gau16UUMA);
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57MPXY87XX/86XX/85XX : Calling Freescale Firmware (3)
• Interrupts are passed to the user directly unless owned by
Freescale
− ISRs owned by Freescale:
ADC
− ISRs flagged by Freescale before being passed to the user:
RFM
KBI
RTI
PWU
LVD
• User must declare pseudo-vectors and handle each interrupt
as if it were its own
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58MPXY87XX/86XX/85XX : Other firmware functions
• Math
− Checksum, CRC8, CRC16, 16-bit multiply,
− Square Root, Weighted average
• Measurements
− Read analog voltage on PTA0, Read analog voltage on PTA1, Read
acceleration with dynamic offset loading
• RF
− Calculate power dynamically, Read RF buffer, Reset RF configuration,
• Timing compensation
− Low-frequency clock compensation, Medium frequency clock compensation,
• Simulated SPI
− Read, write
• LF Reception
− Enable LF, decode data
• Flash
− Write to flash, Erase flash page, Read UniqueID
TM
59Hardware: Schematic Example
XTAL
26 MHz
Matching (RF Emitter)
LF Receiver 315/434MHz
125 kHz
TM
60TM
61Power-saving strategies
• Periodically call TPMS_READ_* routines, but only call
TPMS_COMP_* routines if raw values have shifted significantly
or if a long period of time has elapsed.
• When calling TPMS_COMP_PRESSURE or
TPMS_COMP_ACCELERATION, reutilize existing voltage and
temperature data instead of requesting new data
TM
62Measurement Uses
• Battery Voltage:
− Transmitted to car
− Helps unit determine EOL
• Temperature:
− Used to determine if device is Out Of Operation Range
• Pressure:
− Transmitted to car
− Main function of the device – determine if tires are correctly inflated
• Accelerometer(s):
− Customer IP goes into different functionalities
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63Uses for acceleration
• Determine operation mode (parking/running)
• Determine wheel location
• Determine wheel position
• Determine thread’s wear
• ??
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64TPMS_READ_ACCEL functionality
Zraw (counts)
Moving
Threshold
Park Mode
Time (s)
• TPMS_READ_ACCEL and TPMS_COMP_ACCEL are useful when trying
to determine whether a vehicle is moving or is stopped
• i.e. Set a threshold, determine if the threshold has been passed – Car is
moving
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65TPMS_READ_ACCEL functionality
Zraw (counts)
Time (s)
• TPMS_READ_ACCEL can also be used to determine position
in the tire
• i.e. Each local maximum indicates top-most position in the tire,
each local minimum indicates bottom-most position in the tire
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66TPMS_READ_ACCEL limitations
• Assume 17-inch rim (diameter = 43.18 cm; radius = 21.59 cm)
• Using centrifugal force formula
• Range, is +/- 33.9 km/h
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67Hardware: Layout (Silk Top)
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68Hardware: Layout (Top Layer)
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69Hardware: Layout (L2 GND)
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70Hardware: Layout (L3 Power)
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71Hardware: Layout (Bottom Layer)
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72Hardware: Layout (Silk bottom)
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73TM
74TM
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