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RDAIRBAGPSI5
User Manual
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NXP Semiconductors RDAIRBAGPSI5 User Manual

Freescale Semiconductor
User’s Guide
Document Number: RDAIRBAGPSI5UG
Rev. 2.0, 10/2014
RDAIRBAGPSI5 Airbag Reference Platform
© Freescale Semiconductor, Inc., 2014. All rights reserved.
Figure 1. RDAIRBAGPSI5
Table of Contents
1 Important Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Understanding the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4 Getting to know the Hardware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5 Describing the Device Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6 Installing the Software and Setting up the Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7 Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
8 Board Layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9 Bill of Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
10 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
11 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2 Freescale Semiconductor, Inc.
1 Important Notice
Freescale provides the enclosed product(s) under the following conditions:
This reference design is intended for use of ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY. It is provided as a sample IC pre-soldered to a printed circuit board to make it easier to access inputs, outputs, and supply terminals. This reference design may be used with any development system or other source of I/O signals by simply connecting it to the host MCU or computer board via off-the-shelf cables. Final device in an application will be heavily dependent on proper printed circuit board layout and heat sinking design as well as attention to supply filtering, transient suppression, and I/O signal quality.
The goods provided may not be complete in terms of required design, marketing, and or manufacturing related protective considerations, including product safety measures typically found in the end product incorporating the goods. Due to the open construction of the product, it is the user's responsibility to take any and all appropriate precautions with regard to electrostatic discharge. In order to minimize risks associated with the customers applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. For any safety concerns, contact Freescale sales and technical support services.
Should this reference design not meet the specifications indicated in the kit, it may be returned within 30 days from the date of delivery and will be replaced by a new kit.
Freescale reserves the right to make changes without further notice to any products herein. Freescale makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Freescale assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typical”, must be validated for each customer application by customer’s technical experts.
Freescale does not convey any license under its patent rights nor the rights of others. Freescale products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Freescale product could create a situation where personal injury or death may occur.
Should the Buyer purchase or use Freescale products for any such unintended or unauthorized application, the Buyer shall indemnify and hold Freescale and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Freescale was negligent regarding the design or manufacture of the part.Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners.
© Freescale Semiconductor, Inc. 2014
Important Notice
Freescale Semiconductor 3
Getting Started
2 Getting Started
The RDAIRBAGPSI5 contents include:
• RDAIRBAGPSI5 Airbag Evaluation Platform board
•FTDI Cable
• Warranty card
The RDAIRBAGPSI5-1 contents include:
• RDAIRBAGPSI5-1 Airbag Evaluation Platform board
• PSI5 Satellites modules
• ECU Wiring Harness
•FTDI Cable
• Warranty card
2.1 Jump Start
Freescale’s analog product development boards help to easily evaluate Freescale products. These tools support analog mixed signal and power solutions that include monolithic ICs using proven high-volume SMARTMOS mixed signal technology, and system-in-package devices utilizing power, SMARTMOS and MCU dies. Freescale products enable longer battery life, smaller form factor, component count reduction, ease of design, lower system cost and improved performance in powering state of the art systems.
•Go to www.freescale.com/analogtools
• Locate your kit
• Review your Tool Summary Page
• Look for
• Download documents, software, and other information
Once the files are downloaded, review the user guide in the bundle. The user guide includes setup instructions, BOM and schematics. Jump start bundles are available on each tool summary page with the most relevant and current information. The information includes everything needed for design.
4 Freescale Semiconductor, Inc.
Getting Started
2.2 Required Equipment
Minimum equipment required:
• Power supply (Power Plug or Laboratory Power Supply), with 12 V/2 Amp min current capability
• Oscilloscope (preferably 4-channel) with current probe(s)
• ECU Wiring Harness (included in the RDAIRBAGPSI5-1 kit)
• PSI5 Satellites Sensors (included in the RDAIRBAGPSI5-1 kit)
• Typical loads: 1.2 Ohm/2 Ohm for squibs, switch to ground for DC Sensors, LEDs for GPOs
Recommended equipment for ARP evaluation (GUI):
• FreeMASTER Software installed: http://www.freescale.com/arp
• Airbag Reference Platform FreeMASTER GUI Application: http://www.freescale.com/arp
• USB FTDI cable (Reference: TTL-232R-5V)
All software tools can be downloaded under Software & Tools tab of the RDAIRBAGPSI5 webpage. Registration might be required in order to get access to the relevant files.
Recommended equipment for software development:
• Freescale CodeWarrior 10.5 or greater for Qorivva MCUs (Eclipse IDE) family installed: http://www.freescale.com/arp
• Airbag System Evaluation Software (source code): http://www.freescale.com/arp
• USB A-B cable
• P&E USB Multilink Debugger for Power Architecture:
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=USBMLPPCNEXUS
2.3 System Requirements
• USB-enabled PC with Windows XP or greater
• FTDI Drivers installed for serial communication: http://www.ftdichip.com/Drivers/VCP.htm
Freescale Semiconductor 5
Understanding the System
3 Understanding the System
The Freescale Airbag Reference Platform (ARP) is an application demonstrator system which provides an airbag Electronic Control Unit (ECU) implementation example using complete Freescale standard products for the growing automotive safety segment. The GUI firmware does not constitute a true airbag application but is intended to demonstrate features and capabilities of Freescale's standard products aimed at the airbag market.
The ARP addresses a mid-range airbag market segment, with up to eight squib drivers (for squibs and seatbelt pre-tensioners) and four satellite sensor interfaces supporting four or more high g collision sensors positioned around the vehicle. All other vehicle infrastructure (including seat belt sensors and vehicle communications networks) and ECU functions (including full power supply architecture and a local mid g X/Y safing sensor) are also supported.
The new ARP hardware is implemented using a standard Freescale Qorivva 32-bit microcontroller (MPC560xP), Analog (MC33789 and MC33797). In the case of sensors, the families include both local ECU and PSI5 satellite sensors. The ARP implements a system safety architecture based on the features in the standard products supported by appropriate firmware.
The example ECU is implemented on a single Printed Circuit Board (PCB). Vehicle functions - in principal, satellite sensors, seat belt switches and warning lamps - can be accessed thanks to the ECU cables.
This User Manual is intended to detail the available hardware functionality and related software drivers (firmware) offered in the Freescale ARP.
The high level system block diagram here outlines the way the Freescale standard products are used to implement an example airbag ECU.
6 Freescale Semiconductor, Inc.
Figure 2. RDAIRBAGPSI5 Block Diagram
3.1 Device Features and Functional Description
This reference design features the following Freescale products:
Table 1. Airbag Reference Platform Device Features
Device Description Features
Understanding the System
MPC560xP
MC33789
MMA68xx
MC33797
MC33901
MMA52xx MMA51xx
Qorivva 32-bit Microcontroller
Airbag System Basis Chip (PSI5)
ECU Local X/Y Accelerometer
Four Channel Squib Driver
High Speed CAN Physical Layer
High G Collision Satellite Sensor
• Scalable MCU family for safety applications
• e200z0 Power Architecture 32-bit core up to 64 MHz
• Scalable memory, up to 512 KB flash
• Power supply for complete ECU
• Up to four Satellite Sensor interfaces (PSI5)
• Up to nine configurable switch input monitors for simple switch, resistive and Hall-effect sensor interface
• Safing block and watchdog
• LIN 2.1 physical layer interface
• ±20 g to ±120 g full-scale range, independently specified for each axis
• SPI-compatible serial interface
• 10-bit digital signed or unsigned SPI data output
• Independent programmable arming functions for each axis
• 12 low-pass filter options, ranging from 50 Hz to 1000 Hz
• Four channel high-side and low-side 2.0 A FET switches
• Externally adjustable FET current limiting
• Adjustable current limit range: 0.8 to 2.0 A
• Diagnostics for high-side safing sensor status
• Resistance and voltage diagnostics for squibs
• 8-bit SPI for diagnostics and FET switch activation
• ISO11898-2 and -5 compatible
• Standby mode with remote CAN wake-up on some versions
• Very low current consumption in standby mode, typ. 8 µA
• Excellent EMC performance supports CAN FD up to 2 Mbps
• ±60 g to ±480 g full-scale range
• PSI5 Version 1.3 Compatible (PSI5-P10P-500/3L)
• Selectable 400 Hz, 3 pole, or 4 pole low-pass Filter
• X-axis (MMA52xx) and Z-axis (MMA51xx) available
3.1.1 MPC5602P - Microcontroller
This microcontroller is a member of the highly successful Qorivva MPC560xP family of automotive microcontrollers.
It belongs to an expanding range of automotive-focused products designed to address chassis applications as well as airbag applications. The advanced and cost-efficient host processor core of this automotive controller family complies with the Power Architecture® embedded category. It operates at speeds of up to 64 MHz and offers high performance processing optimized for low power consumption. It capitalizes on the available development infrastructure of current Power Architecture® devices and is supported with software drivers, operating systems and configuration code to assist with users implementations.
Freescale Semiconductor 7
Understanding the System
3.1.2 MC33789 - Airbag System Basis Chip
This device implements all vehicle sensor interfaces and the airbag system support functions:
3.1.2.1 Power Supply Block
• A switched-mode power supply DC-DC converter in a boost configuration to generate the high voltage level (33 V), in which energy is stored in the autarky capacitor, and used to allow continued operation of the airbag system for a defined time following a collision, which leads to disconnection of the battery
• A switched-mode power supply DC-DC converter in a buck configuration, to efficiently step down the boost supply to a level suitable for supplying the satellite sensors interfaces (9.0 V) and further regulators, for the local ECU supplies
• A switched capacitor charge pump to double the output of the buck converter, for use in supplying the necessary voltage for the PSI5 sync pulse generation (18 V)
• A linear regulator to provide the local logic supply (5.0 V) for ECU devices i.e. microcontroller, local sensor, squib driver
3.1.2.2 Safing Block
This block includes a SPI monitor which inputs all inertial sensors (PSI5 satellites and onboard sensors) read by the microcontroller over the sensor SPI interface, and compares it to pre-defined threshold acceleration values for each local and vehicle collision sensor. Based on this comparison, where the threshold is exceeded in three consecutive acquisition cycles, the system is armed by enabling the safing outputs, which in turn enables the squib drivers, so that the application can fire the necessary squibs based on the airbag algorithm results.
3.1.2.3 DC Sensors Interface
A low speed (DC) interface which connects to resistive, simple switch and hall effect sensors which are used to check whether seat belts are being worn through seat belt switches and seat position through seat track sensors.
3.1.2.4 PSI5 Satellite Sensors Interface
Four Satellite sensors interfaces, which connect to collision sensors distributed around the vehicle. The interfaces are implemented based on the PSI5 V1.3 specification, and can operate in synchronous modes. It detects current drawn by the satellite and translates the current-modulated satellite messages into digital data, which the MCU retrieves via the SPI interface.
3.1.2.5 LIN Physical Layer
For connection to vehicle diagnostic interface (K-line) or Occupant Classification System.
3.1.2.6 Lamp Driver
A flexible high or low-side driver which can be configured in hardware which supports PWM driven LED or warning lamp driver.
3.1.2.7 Diagnostics
A number of measures which allow diagnosis of implemented functions on the system basis chip, e.g. all voltage supplies including power transistor temperature monitors, autarky capacitor ESR, etc.
3.1.2.8 Additional Communication Line
MC33789 is designed to support the Additional Communication Line (ACL) aspect of the ISO-26021 standard, which requires an independent hardwired signal (ACL) to implement the scrapping feature.
8 Freescale Semiconductor, Inc.
Understanding the System
3.2 MMA6813KW - ECU Local Sensor
The ECU local sensor acceleration data is used by the airbag application to cross check the acceleration data received from the satellite collision sensors, to confirm that a collision is really happening, and that airbags need to be deployed.
The local sensor used in the ARP is dual channel, and confirms both frontal and side impacts. In addition, the MMA68xx includes its own safing block, which will compare the measured acceleration to configurable thresholds and set safing outputs accordingly. This function is used in the ARP to enable the squib drivers, and therefore be an independent part of the system safing architecture - both the safing blocks in the system basis chip and in the local sensor must enable the squib drivers before the application is able to fire the appropriate squibs.
3.3 MC33797 - Four Channel Squib Driver
Each channel consists of a high-side and a low-side switch. The ARP uses two MC33797 devices connected in cross-coupled mode, i.e. high-side switch from one device and low-side switch from the other, connected to each squib or seat belt pre-tensioner. This ensures no single point of failure in the squib output stage.
The MC33797 implements a comprehensive set of diagnostic features that allows the application to ensure that the squib driver stage is operating correctly.
3.4 MMA5xxx - High G Satellite Collision Sensor
A single channel acceleration sensor operating in the range of 60 - 480g (depending on G-cell fitted), which includes a PSI5 V1.3 interface for direct connection to the system basis chip. The device can operate in either asynchronous (point-to-point single sensor connection) or synchronous (bus mode with multiple sensors connected to each interface) mode. The device can be used either for frontal collisions or side impacts. For more information about PSI5, please refer to the PSI5 standard specification for airbag systems:
http://psi5.org/
Freescale Semiconductor 9
Getting to know the Hardware
24-pin connector 32-pin connector
4 Getting to know the Hardware
4.1 Overview
RDAIRBAGPSI5 is an eight loops airbag system ECU. Figure 3 shows all the main components of an airbag ECU hardware. Table 2 lists all the functions performed by each component.
Figure 3. Board Description
Table 2. Board Description
Name Definition
x2 4ch Squibs Driver MC33797 x2 Four channels Squibs Driver configured in cross-coupled mode to make an eight firing loops airbag
system
Central Accelerometer MMA68xx Central Accelerometer, also called Local Safing Sensor, designed for use in automotive airbag systems
CAN HS Transceiver MC33901 Physical interface between the CAN protocol controller of an MCU and the physical dual wires of the
CAN bus
JTAG Connector P&E USB Multilink Debugger
FTDI Connector (RS232) USB to serial communication connector for GUI application
32-bit MCU MPC5602P Qorivva Power Architecture MCU for Chassis and Safety Application
PSI5 Airbag System Basis Chip MC33789 Airbag System Basis Chip (SBC) with Power Supply and PSI5 Sensor Interface
On-Board Front Airbags Deployment LEDs 2x LEDs used to indicate a front impact Deployment event: Front Driver and/or Front Passenger
10 Freescale Semiconductor, Inc.
Getting to know the Hardware
REDD2,3,4,5
OrangeD6
GreenD7
YellowD1
Table 2. Board Description (continued)
Name Definition
On-Board Side Airbags Deployment LEDs 2x LEDs used to indicate a side impact Deployment event: Rear Right and/or Rear Left
Energy Reserve Capacitor Autarky Capacitor used as Energy Reserve in case of Battery disconnection
4.2 LED Display
This section describes the LEDs on the lower portion of the RDAIRBAGPSI5 board.
Figure 4. LED Locations
The following LEDs are provided as visual output devices for the RDAIRBAGPSI5 board:
1. LED D1 indicates when a System Reset occurred (LED color: Yellow).
2. LED D2 first indicates MC33789 is correctly initialized only during INIT phase. Then, it is used to display Front Passenger deployment during GUI Application mode (LED color: Red).
3. LED D3 first indicates MMA68xx is correctly initialized only during INIT phase. Then, it is used to display Rear Right Side deployment during GUI Application mode (LED color: Red).
4. LED D4 first indicates MC33797 are correctly initialized only during INIT phase. Then, it is used to display Front Driver deployment during GUI Application mode (LED color: Red).
5. LED D5 first indicates MCU is correctly initialized only during INIT phase. Then, it is used to display Rear Left Side deployment during GUI Application mode (LED color: Red).
6. LED D6 indicates when a FCU fault is detected by MCU (LED color: Orange). Note: If no FCU faults are detected, LED is turned ON.
7. LED D7 indicates MCU Software is running (LED color: Green).
Freescale Semiconductor 11
Getting to know the Hardware
Pin 2
4.3 Connectors
This section discusses the ARP 32-pin and 24-pin positions and their descriptions.
Figure 5. J1 32-pin Connector Location
Table 3: 32-pin Connector Pin List
Position
1 GND Ground Signal 17 IN6 Port 6 of input monitor for DC sensor
2 VBAT Battery Voltage 18 IN5 Port 5 of input monitor for DC sensor
3 GND Ground Signal 19 IN4 Port 4 of input monitor for DC sensor
4 VBAT Battery Voltage 20 IN3 Port 3 of input monitor for DC sensor
5 NC Not connected 21 IN2 Port 2 of input monitor for DC sensor
6 NC Not connected 22 IN1 Port 1 of input monitor for DC sensor
7 OUT2_S Source pin of configurable output FET 2 23 CANH CAN Bus High Signal
8 OUT2_D Drain pin of configurable output FET 2 24 CANL CAN Bus Low Signal
9 OUT1_D Drain pin of configurable output FET 1 25 HI_4 Source of the Squib Driver High-side switch 4
10 OUT1_S Source pin of configurable output FET 1 26 LO_4 Drain of the Squib Driver Low-side switch 4
11 LIN_GND LIN Ground 27 HI_3 Source of the Squib Driver High-side switch 3
12 LIN LIN Signal 28 LO_3 Drain of the Squib Driver Low-side switch 3
13 NC Not connected 29 HI_2 Source of the Squib Driver High-side switch 2
14 IN9 Port 9 of input monitor for DC sensor 30 LO_2 Drain of the Squib Driver Low-side switch 2
15 IN8 Port 8 of input monitor for DC sensor 31 HI_1 Source of the Squib Driver High-side switch 1
Signal name
Description Position
Signal name
Description
16 IN7 Port 7 of input monitor for DC sensor 32 LO_1 Drain of the Squib Driver Low-side switch 1
12 Freescale Semiconductor, Inc.
Table 4: 24-pin Connector List
Getting to know the Hardware
Figure 6. J2 24-pin Connector Location
Position
33 HI_5 Source of the Squib Driver High-side switch 5 45 NC Not Connected
34 LO_5 Drain of the Squib Driver Low-side switch 5 46 NC Not Connected
35 HI_6 Source of the Squib Driver High-side switch 6 47 NC Not Connected
36 LO_6 Drain of the Squib Driver Low-side switch 6 48 NC Not Connected
37 HI_7 Source of the Squib Driver High-side switch 7 49 PSI5_1OUT PSI5 Channel1 Signal line
38 LO_7 Drain of the Squib Driver Low-side switch 7 50 PSI5_1GND PSI5 Channel1 Ground line
39 HI_8 Source of the Squib Driver High-side switch 8 51 PSI5_2OUT PSI5 Signal Channel2 line
40 LO_8 Drain of the Squib Driver Low-side switch 8 52 PSI5_2GND PSI5 Channel2 Ground line
41 GND Ground signal 53 PSI5_3OUT PSI5 Channel3 Signal line
42 GND Ground signal 54 PSI5_3GND PSI5 Channel3 Ground line
43 NC Not Connected 55 PSI5_4OUT PSI5 Channel4 Signal line
44 NC Not Connected 56 PSI5_4GND PSI5 Channel4 Ground line
Signal name
Description Position Signal name Description
Freescale Semiconductor 13
Describing the Device Functions
5 Describing the Device Functions
The RDAIRBAGPSI5UG Airbag Reference Platform is aimed to cover all major functions of a true airbag system application.
The following section describes individual functions and available view using the GUI:
5.1 MC33789 - Airbag System Basis Chip
5.1.1 Power Supply - Boost Converter and Energy Reserve
Table 5. Power Supply - Boost Converter and Energy Reserve
Define Function Config Register Diagnosis Comment
MC33789 Energy Reserve Supply PS_CONTROL AI_CONTROL
Default setting for the boost converter is ON and will start up when VBATT exceeds a predefined limit. Initially, the boost converter will charge a small capacitor. Default setting for the energy reserve is OFF to prevent excessive inrush current at key on. The firmware must turn the energy reserve on through the PS_CONTROL register once VBOOST is stable. Firmware can monitor VBOOST through the analog output pin selected through AI_CONTROL register. After the energy reserve is turned on, the large energy reserve capacitor (min 2200 µF) will be charged.
5.1.2 Power Supply - Energy Reserve Capacitor ESR Diagnostic
Table 6. Power Supply - Energy Reserve Capacitor ESR Diagnostic
Define Function Config Register Diagnosis Comment
MC33789 Energy Reserve
Capacitor Diagnostic
During ESR diagnostic, the energy reserve capacitor is slightly discharged and the firmware can calculate, based on the discharge rate, the value of the capacitor's equivalent series resistance (ESR) - this is a measure of the condition of the capacitor.
ESR_DIAG ESR_DIAG
5.1.3 Power Supply - Buck Converter
Table 7. Power Supply - Buck Converter
Define Function Config Register Diagnosis Comment
MC33789 Vcc5, DC Sensor and
Satellite Sensor Supply
Buck converter is internally enabled when the VBOOST voltage is above the under-voltage lockout threshold. The firmware cannot disable the Buck converter in the RDAIRBAGPSI5 application.
PS_CONTROL AI_CONTROL
14 Freescale Semiconductor, Inc.
5.1.4 Power Supply - SYNC Pulse Supply
Table 8. Power Supply – SYNC Pulse Supply
Define Function Config Register Diagnosis Comment
Describing the Device Functions
MC33789 Satellite Sensor SYNC
Pulse Supply
Default setting for the SYNC supply is OFF. Firmware needs to turn the SYNC supply on through PS_CONTROL register only if the satellite sensors are operating in synchronous mode. Firmware can monitor VSYNC voltage through the analog output pin selected through the AI_CONTROL register.
PS_CONTROL AI_CONTROL
5.1.5 Power Supply - ECU Logic Supply
Table 9. Power Supply - ECU Logic Supply
Define Function Config Register Diagnosis Comment
MC33789 Linear Regulator – –
The internal ECU logic supply is always on and firmware has no configuration to perform.
5.1.6 Safing Block - Sensor Data Thresholds
Table 10. Safing Block - Sensor Data Thresholds
Define Function Config Register Diagnosis Comment
MC33789 Threshold T_UNLOCK,
SAFE_TH_n
–
In order to be able to change the sensor data threshold value or values at which the ARM/DISARM pins are set to their active states (i.e. the system is armed when a sensor value exceeds the defined threshold), a secure firmware sequence must be carried out to unlock the threshold register using T_UNLOCK. Once that is done, the threshold can be changed by firmware through the SAFE_TH_n register.
Notes: There is no special firmware required to input sensor data into the safing block. The SPI protocol on the sensor SPI interface is the same to both the local sensor and the satellite sensor interfaces on the system basis chip, and whenever the microcontroller reads a sensor value, the response from the sensor or system basis chip is recognized as being sensor data, and is automatically read into the safing block. The only requirement the application has to meet is that the sensor data is read in the correct sequence, starting with the local sensor X-axis data followed by the Y-axis, and then the satellite sensor interfaces on the system basis chip.
5.1.7 Safing Block - Diagnostics
Table 11. Safing Block - Diagnostics
Define Function Config Register Diagnosis Comment
MC33789 Linear Regulator – SAFE_CTL
The firmware has the capability to change the mode in which the safing block is operating, so that diagnosis of the ARM/DISARM pins can be diagnosed or the scrapping mode (i.e. the system is armed when no sensor data exceeds any threshold, used to fire all squibs when a vehicle is being scrapped) can be entered. Either of these changes is only possible at startup prior to the safing block entering normal operation.
Freescale Semiconductor 15
Describing the Device Functions
5.1.8 DC Sensors
Table 12. DC Sensors
Define Function Config Register Diagnosis Comment
MC33789 Seat belt/Seat track
sensor interface
The firmware must select which DC sensor is active and which supply voltage is used on that sensor through the DCS_CONTROL register. The firmware must also select the correct sensor to be read through the analog output pin using the AI_CONTROL register. Note that both registers can be returned to their default state by a correct write to the DIAG_CLR register.
DCS_CONTROL, AI_CONTROL
–
5.1.9 PSI5 Satellite Sensor Interface
Table 13. PSI5 Satellite Sensor Interface
Define Function Config Register Diagnosis Comment
MC33789 Satellite Sensor LINE_MODE,
LINE_ENABLE
The firmware must select the correct mode of operation of the satellite sensor interface and enable each interface individually. The interfaces should be enabled one at a time to reduce current inrush.
When the interface is enabled, the satellite sensor will automatically send its initialization data, and the firmware must handle this data to ensure the sensor is operating correctly.
5.1.9.1 LIN Physical Layer
Table 14. LIN Physical Layer
–
Define Function Config Register Diagnosis Comment
MC33789 LIN physical layer LIN_CONFIG –
The firmware has the potential to change the configuration of the LIN physical layer, but the default setting is the most common configuration.
A special mode exists which allows the Manchester encoded data from a satellite sensor to be monitored on the LIN RXD output pin, for example in case MCU has a PSI5 peripheral module embedded.
5.1.9.2 Lamp Driver
Table 15. Lamp Driver
Define Function Config Register Diagnosis Comment
MC33789 Lamp driver GPOn_CTL GPOn_CTL
The firmware must configure whether the driver is a high or low-side switch, and the PWM output duty cycle. In the response to the command, the firmware can check that high or low thresholds on the pins have been exceeded, and whether an over-temperature shutdown has occurred.
As part of the application, the warning lamp should be turned on at key on, kept illuminated until the startup diagnostic procedure has completed, and the system is ready to start operating.
16 Freescale Semiconductor, Inc.
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