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• Functional safety considerations
• Applications Use case
• Evaluation Tool Demonstration
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• 15 UMEMS Designs
− Three g-ranges (low,med,high)
• 2 ASIC Designs (LL18UHV)
Differentiating Points
Configurable Sensor Range.
Extended Functional Safety Mechanism.
Product Features − Independent X-Axis, Y-Axis or Z-Axis Ranges for each Channel
− Up to a 4th order Low Pass Filter with Rolloff Frequency Options from 12.5Hz to 1500Hz.
− DSI3/PSI5 V2.1/SPI/I2C compatible.
− Versatility of Data Output: Raw/Low Pass Filtered/High Pass Filtered data, temperature Data.
− Data Size range from 10bits to 16bits.
− Extended Functionnal Safety capability.
− Acceleration range: 1.5 – 480 g
− 3.3V to 20V supply voltage
− Output sampling rate depending of used communication protocol up to 4.38kHz (PSI5).
Typical Applications − Safety
Electronic Stability Control Sensor
Availability
The purpose of the Gen 6 product portfolio is to:
• replace the existing Gen 4 portfolio of devices with feature enhanced and cost
reduced devices
Gen 4
devices Function
Gen 4
g-range
Mesquite
Sycamore Dual Channel XY SPI Main ECU crash sensor 20 to 125g Thornapple 15g to 150g
Oroya Single Channel X or Z PSI5 Satellite Crash Sensor 60 to 480g Laurel 50g to 480g
Cardon
Agave3
Single Channel X or Z DSI2/3 Satellite Crash
Sensor 25 to 375g Laurel 15g to 480g
Opuntia Dual Channel XY SPI Low g Main ECU ESC Sensor 3.5 to 5g Low g Dual 1.5g to 20g
Colossus
Titan
Crash Sensor 1.5g to 8g
Med / Low g
• PSAT – Pressure Sensor Satellite
− Engine Management BAP application
− Engine Management MAP application
− Engine Management Turbo application
− Engine Management LPG applications
• Film assisted molding technology
Sample now for PSAT
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Product Features
− 40 kPa – 140 kPa Absolute Pressure Range
− Selectable 370Hz, 2-Pole or 400Hz, 3-Pole Low Pass Filter for Absolute Pressure
− DSI3/PSI5 V2.1/SPI/I2C compatible.
− Versatility of Data Output: Raw/Low Pass Filtered/High Pass Filtered data, temperature Data.
− 10 bit data length for relative pressure
− Extended Functional Safety capability.
− 3.3V to 20V supply voltage
Typical Applications
Availability : Sampling now !
02.
• Temperature Range: -40 C to 125 C
• Internal Oscillator with Verification via External COUNT Register Access
• Digital Signal Processing
− C2V, Sigma Delta Modulator and Sinc Filter
− Low Pass Filter options from 25 Hz to 1500 Hz, up to 4-pole
− Optional 0.04Hz Offset Cancellation High Pass Filter with selectable output rate limiting
• DSI3 Compatible
− Command Response Mode (CRM) for device configuration
− Periodic Data Collection Mode (PDCM) for normal acceleration data transfers.
− Optional Background Diagnostic Mode during PDCM
• AKLV27 Compatible, PSI5 V2.1 Compatible, Airbag Substandard
− PSI5-P10P-500/3L and PSI5-P10P-500/4H data transmission
− High Speed customer programmability through PSI5 interface
− Daisy chain support with external switch
• 32-bit SPI
− Error Detection via CRC Status and Source Identification
• Independent Arming Functions for each channel
− Up to a 16 sample Moving Average calculated on offset cancelled data
− 2 Independent Programmable Thresholds per channel up to ±25% of full scale
Transducer
• X-Axis and Z-Axis UMEMS (Unique Range for each Channel)
• Bidirectional Self Test, Independently Controlled for each Channel
Package
• 16 pin QFN 4 mm x 4 mm x 1.45 mm
• Inspectable Solder Joints
− 40kPa – 140kPa Absolute Pressure Range
− -40C – 125C Operating Temperature Range
• ASIC
− Temperature range: -40°C – 125°C
− DSP Chain
370 Hz, 2-Pole LPF for absolute pressure
0.16Hz, 1-Pole LPF for P0 value
10-Bit P/P0 output
− Sensitivity error: +/- 7%
− DSI3, PSI5-v2.1 compatible
− AKLV29 v1.3 compatible
− Pressure Range : 40kPa – 140kPa
• PACKAGE
− Pb free 4mm X 4mm X 1.98mm Cavity QFN (FAM)
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− Crash detection
− Electronic Stability Control
− Electric Parking Brake control
− > Crash detection
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Arming Function
Used as a safety mechanism to verify decisions made by other devices in the system using the sensor data.
• Mode:
For more information about DSI3 protocol : http://www.dsiconsortium.org/securepage.php
• GEN6 products are compatible with the new DSI3 industry standard, revision 1.00.
• Address Assignment
− Discovery mode
• Command and Response Mode (CRM)
− Complete self test.
− Configure the device
− Locked configuration to prevent any change
− Continuous Data transmission.
For more information about PSI5 protocol : http://psi5.org/specification/
• GEN6 products are compatible with the AKVL29 V2.1 industry standard which requires PSI5 V1.3 compatibility
• Initialization
− Initialization phase 2 data is transmitted as specified in AKLV29 V1.3. All 32 data fields are transmitted 4 times.
− Initialization data includes:
The protocol revision
The sensor manufacturer
The sensor type
A production date code
A serial number
• The initialization data is determined by the satellite module supplier and thus user programmable in NVM.
• Continuous Data Transmission
Synchronous/Asynchronous Parallel Mode
10-16 Bit Data.
Parity/CRC Error Detection
500ms repetition rate
125/189kBaud bit rate
−Device Initialization
Multiples data sources
Sensor data request
• Safety Mechanism:
− Activity or technical solution to detect / avoid / control failures or mitigate their harmful effects.
− The safety mechanism is either able to switch to or maintain the item in a safe state or able to alert the driver such that the driver is expected to control the effect of the failure.
• Safety Goals
− Determined for each hazardous event
− ASIL determined for the hazardous event is to be assigned to the corresponding safety goal.
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• Hazard analysis
• Determine ASIL
• Functional safety concept :redundancy concept comprising a control channel and an independent monitoring channel.
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− Over/Undervoltage monitoring
− Self-Test verification
− Temperature monitoring
− 2 bits status field with each SPI command
− Register read verification
• DSI3 Safety Mechanism
− 4 bits status field with each DSI3 command
− Register read verification
• PSI5 Safety Mechanism
− Automatic Self-test
− 1 Parity bit / 3 bits CRC with each sensor data transmission
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Excerpt from Safety Manual – DSI3 Safety Mechanisms
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Low-g
Z
Low-g
Z
• Overview
− For the automotive side airbag system, the Thornapple device is typically mounted inside the vehicle front/back bumpers.
− Sensor Data is transmitted from the device to a main controller for data processing via a 2- wire communications interface that also supplies power.
• Sensor Data
− The main sensor data transmission necessary for the automotive side airbag system is 1 axis acceleration, transmitted as offset cancelled acceleration in g.
− The acceleration is provided by either DSI3, PSI5 with 10-bit,12-bit or 16-bits precision.
− The required acceleration range from 50g to 500g depending of the sensor’s location.
• Vehicle locations
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• Overview
− The device is typically located in the passenger compartment to sense the vehicle tilt,
− Sensor and main controller are located on the same module.
• Sensor Data
− The main sensor data transmission necessary for the automotive side airbag system is 2 axis acceleration, transmitted as acceleration in g.
− The acceleration is provided by either SPI or I2C with 12-bit or 16-bits precision.
− The required acceleration range for rollover application can vary from 1.5g to 20g.
• Vehicle locations
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• Overview
− PSAT_DBAP1 can be used as a remote relative pressure sensor in an automotive airbag system. The device is typically located in the vehicle door to sense the rapid pressure changes due to a vehicle door intrusion for the purposes of side airbag deployment. Sensor Data is transmitted from the device to a main controller for data processing via a 2- wire communications interface that also supplies power.
• Sensor Data
− Relative pressure, transmitted as DP/P0 is required for crash detection.
− P0 is an average value of the absolute pressure using a low pass filter that limits the P0 change to ~0.4kPa/s. DP is calculated by subtracting the P0 from the absolute pressure value.
− On Startup it is necessary to transmit the average absolute pressure. Some DSI3 systems may also require a method to continuously transmit both absolute pressure and relative pressure. Some DSI3 systems may require a method to transmit the device temperature either on startup, continuously, or both.
• Vehicle locations
− For the automotive side airbag system, the PSAT_DBAP1 device is typically mounted inside the vehicle door cavity with the pressure port facing outward.
− In this location, the operating temperature requirement is -40°C to +105°C.
• Advantages over Accelerometer
− Fast firing decision
• Pressure satellites are used in the front bumper
for pedestrian protection
• Idea is to detect a change in pressure due to a
collision with a human, then raise the bonnet or
add an airbag for soft landing to protect the
body.
NXP Automotive Sensor Evaluation Freedom Evaluation Platform for NXP Automotive Sensor
X-FRDM-QFN4SKT-A X-FSLGEN6SKTIACC FSLGEN6SKTPRES
− PSI5 V2.1.
NXP Automotive Sensor Evaluation
I2C0
I2C1
Sensor
Interface
Range
LPF
Tool & Hardware available upon request