ARDRM, Airbag Reference Demonstrator Reference Manual

Freescale Semiconductor
Reference Manual
ARDRM
Rev. 3.0, 4/2012
Airbag Reference Demonstrator
Reference Manual
© Freescale Semiconductor, Inc., 2012. All rights reserved.
Important Notice
Freescale provides the enclosed product(s) under the following conditions:
This demonstrator 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 demonstrator 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. This demonstrator is not intended to represent a final design recommendation
for any particular application. 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.
As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and
therefore may not meet the technical requirements of the directive. Please be aware that the products received may not be
regulatory compliant or agency certified (FCC, UL, CE, etc.).
Should this demonstrator 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,
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limitation consequential or incidental damages. “Typical” parameters can and do vary in different applications and actual
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Airbag Reference Demonstrator, Rev. 3.0
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Freescale Semiconductor
Table of Contents
Paragraph
Number
Page
Number
Chapter 1 Introduction
1.1
Relevant Documents .......................................................................................................1
Chapter 2 ARD System Outline
Chapter 3 Standard Products Description
3.1
3.2
3.3
3.4
3.5
MC9S12XEG128MAA - Microcontroller ..........................................................................3
MC33789 – Airbag System Basis Chip ...........................................................................3
3.2.1 Power Supply Block...............................................................................................3
3.2.2 Safing Block...........................................................................................................3
3.2.3 DC Sensors ...........................................................................................................3
3.2.4 PSI5 Satellite Sensors ...........................................................................................3
3.2.5 LIN Physical Layer.................................................................................................3
3.2.6 Lamp Driver ...........................................................................................................3
3.2.7 Diagnostics ............................................................................................................3
MC6801QR2 - ECU Local Sensor ...................................................................................3
MC33797 – Four Channel Squib Driver ..........................................................................4
MMA5xxxWR2 – High G Satellite Collision Sensor .........................................................4
Chapter 4 Function Description
4.1
4.2
4.3
4.4
MC33789 – Airbag System Basis Chip ...........................................................................5
4.1.1 Power Supply – Boost Converter and Energy Reserve.........................................5
4.1.2 Power Supply – Energy Reserve Capacitor ESR Diagnostic ................................5
4.1.3 Power Supply – Buck Converter............................................................................5
4.1.4 Power Supply – SYNC Pulse Supply.....................................................................5
4.1.5 Power Supply – ECU Logic Supply .......................................................................5
4.1.6 Safing Block – Sensor Data Thresholds ................................................................6
4.1.7 Safing Block – Diagnostics ....................................................................................6
4.1.8 DC Sensors ...........................................................................................................6
4.1.9 Satellite Sensor Interface.......................................................................................6
LIN Physical Layer 6
Lamp Driver 7
Diagnostics 7
MMA6801QR2 – Local ECU Acceleration Sensor ..........................................................7
4.2.1 Configuration - General .........................................................................................7
4.2.2 Configuration – Axis Operation..............................................................................7
4.2.3 Configuration – Arming Operation .........................................................................7
4.2.4 Configuration – Arming Threshold .........................................................................8
4.2.5 Status.....................................................................................................................8
MM33797 – Four Channel Squib Driver (FCS) ...............................................................8
MMA5xxxWR2 – High G Satellite Collision Sensor .........................................................8
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TOC-1
Table of Contents
Chapter 5 Airbag Reference Demonstrator Firmware and Setup
5.1
5.2
5.3
5.4
5.5
Airbag Reference Demonstrator Demo ...........................................................................9
Warnings .........................................................................................................................9
Airbag Reference Demonstrator PCB Detail Description .............................................. 10
Airbag Reference Demonstrator - GUI .......................................................................... 10
5.4.1 Firmware downloading - GUI version .................................................................. 10
5.4.2 Hardware and Software Setup............................................................................. 11
5.4.3 GUI Demonstration .............................................................................................. 11
Debug mode 11
Application Mode 12
Airbag Reference Demonstrator - “Application” ............................................................. 13
5.5.1 Firmware Downloading - “Application Demonstrator” .......................................... 14
5.5.2 Airbag Reference Demonstrator - “Application”................................................... 15
Chapter 6 Software - Boot Assist Module
6.1
Boot Assist Module (BAM) ............................................................................................. 17
6.1.1 Example of the BAM source code ....................................................................... 17
Chapter 7 Software - Basic Operating System
7.1
7.2
7.3
Acquisition Phase ..........................................................................................................20
7.1.1 Source code of the Acquisition phase ................................................................. 21
Decision Phase .............................................................................................................. 23
7.2.1 Example of the API Source Code Used in Decision Phase - Front Decision ...... 23
Deployment Phase ........................................................................................................24
7.3.1 Example of the API Source Code Used in Deployment Phase ........................... 25
Appendix A SW Concept ........................................................................................................27
A.1 Airbag System Basis Chip SW Driver ............................................................................27
A.2 ASBC API parameters detail descriptions .....................................................................28
A.3 Central Accelerometer Driver ........................................................................................ 31
A.4 ACC Parameters Detail Descriptions ............................................................................32
A.5 SQUIB Driver ................................................................................................................. 34
A.6 SQUIB Parameters Detail Descriptions ......................................................................... 35
Appendix B Airbag Reference Demonstrator Implementation details .................................... 37
B.1 Airbag Reference Demonstrator Schematics ................................................................ 37
B.2 ARD Placement and Layout ..........................................................................................42
B.3 Bill of Materials .............................................................................................................. 43
Appendix C Acronyms ............................................................................................................45
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Introduction
Chapter 1 Introduction
The Freescale Airbag Reference Demonstrator (ARD), a SafeAssure
solution, is an application demonstrator system that provides an airbag
ECU implementation example using Freescale standard products and
firmware. It exercises the primary functions in those products as well as
any diagnostic features. The firmware does not constitute a true airbag
application, but is intended to demonstrate features and capabilities of
Freescale’s standard products for the airbag market.
The current ARD 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 ARD hardware is implemented using standard Freescale
microcontroller, analog and sensor family products. In the case of
sensors, the families include both local ECU and satellite sensors. The
ARD 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 – are implemented on separate pcbs and mounted on a
base plate.
This Reference Manual is intended to detail the available hardware
functionality and related software drivers (firmware) offered in the
Freescale ARD.
1.1
Relevant Documents
[1]
Airbag Reference Demonstrator – ARD Reference Manual
[2]
MC33789 – System Basis Chip Data Sheet
[3]
MMA68xx - SPI Medium-g Dual Channel Local ECU Sensor Data Sheet
[4]
MC33797 – Four Channel Squib Driver IC Data Sheet
[5]
MMA5xxxWR2 - PSI5 High-g Satellite Sensor Data Sheet
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ARD System Outline
Chapter 2 ARD System Outline
The high level system block diagram here outlines the way the Freescale standard products are used to implement an example
airbag ECU.
•
MC9S12XEG128MAA – Microcontroller
•
MC33789 – Airbag System Basis Chip
•
MMA6801QR2 – ECU Local X/Y Accelerometer
•
MM33797 – Four Channel Squib Driver
•
CAN Phy – High Speed CAN Physical Layer
•
MMA5xxxWR2 – High G Collision Satellite Sensor
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Standard Products Description
Chapter 3 Standard Products Description
All devices used in the Freescale ARD are standard products and those devices are described here.
3.1
MC9S12XEG128MAA - Microcontroller
This microcontroller is a member of the highly successful S12 family of automotive microcontrollers that includes flexible Flash
memory, which allows cost efficient implementation of internal EEPROM emulation, and a rich selection of peripherals to support
an efficient system connection.
3.2
MC33789 – Airbag System Basis Chip
This device implements all vehicle sensor interfaces and the airbag system support functions.
3.2.1 Power Supply Block
•
A switch 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 system for a defined time
following a collision, which leads to disconnection of the battery
•
A switch 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 charge pump to double the output of the buck converter, to supply the necessary voltage for the PSI5 sync pulse
generation (18 V), to facilitate operation of the satellite sensor interfaces in synchronous mode, and therefore more than
one sensor per interface. This is only enabled if more than one satellite sensor per interface is required
•
A linear regulator to provide the local logic supply (5.0 V) for ECU devices i.e. microcontroller, local sensor, squib
driver,...
3.2.2 Safing Block
This block includes an SPI monitor which inputs sensor data 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.
3.2.3 DC Sensors
A low speed (D.C.,) interface which connects to resistive 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.
3.2.4 PSI5 Satellite Sensors
Satellite sensors interfaces, which connect to collision sensors distributed around the vehicle. The interfaces implement the PSI5
V1.3 specification, and can operate in asynchronous and synchronous modes.
3.2.5 LIN Physical Layer
For connection to vehicle diagnostic interface (K-line) or Occupant Classification System.
3.2.6 Lamp Driver
A high or low side driver which can be configured in hardware which supports PWM driven LED or warning lamp driver.
3.2.7 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.
3.3
MC6801QR2 - 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.
Airbag Reference Demonstrator, Rev. 3.0
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3
Standard Products Description
The local sensor used in the ARD is dual channel, and confirms both frontal and side impacts. In addition, the MC6801QR2
includes it’s own safing block, which will compare the measured acceleration to configurable thresholds and set safing outputs
accordingly. This function is used in the ARD 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.
3.4
MC33797 – Four Channel Squib Driver
Each channel consists of a high side and a low side switch. The ARD 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.
3.5
MMA5xxxWR2 – 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.
Airbag Reference Demonstrator, Rev. 3.0
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Freescale Semiconductor
Function Description
Chapter 4 Function Description
The following section describes individual functions and how they relate to firmware.
4.1
MC33789 – Airbag System Basis Chip
4.1.1 Power Supply – Boost Converter and Energy Reserve
Device
Function
Config Register
Diagnosis
MC33789
Energy Reserve Supply
PS_CONTROL
AI_CONTROL
Comment
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 current inrush 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.
4.1.2 Power Supply – Energy Reserve Capacitor ESR Diagnostic
Device
Function
Config Register
Diagnosis
MC33789
Energy Reserve Capacitor
Diagnostic
ESR_DIAG
ESR_DIAG
Comment
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 effective series resistance – this is a measure of the condition of the capacitor.
4.1.3 Power Supply – Buck Converter
Device
Function
Config Register
Diagnosis
MC33789
Satellite Sensor Supply
PS_CONTROL
AI_CONTROL
Comment
Default setting for the buck converter is ON and will start up when VBOOST starts up. Firmware can monitor VBUCK through the
analog output pin selected through AI_CONTROL register.
4.1.4 Power Supply – SYNC Pulse Supply
Device
Function
Config Register
Diagnosis
MC33789
Satellite Sensor SYNC Pulse
Supply
PS_CONTROL
AI_CONTROL
Comment
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 through the analog output pin selected
through the AI_CONTROL register.
4.1.5 Power Supply – ECU Logic Supply
Device
Function
Config Register
Diagnosis
MC33789
Linear Regulator
-
-
Comment
The internal ECU logic supply is always on and firmware has no configuration to perform.
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Function Description
4.1.6 Safing Block – Sensor Data Thresholds
Device
Function
Config Register
Diagnosis
MC33789
Threshold
T_UNLOCK,
SAFE_TH_n
-
Comment
In order to be able to change the sensor data threshold value or values at which the ARM/DISARM pin are set to active (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.
NOTE
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.
4.1.7 Safing Block – Diagnostics
Device
Function
Config Register
Diagnosis
MC33789
Linear Regulator
-
SAFE_CTL
Comment
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.
4.1.8 DC Sensors
Device
Function
Config Register
Diagnosis
MC33789
Seat belt/Seat track sensor
interface
DCS_CONTROL,
AI_CONTROL
-
Comment
The firmware must select which 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.
4.1.9 Satellite Sensor Interface
Device
Function
Config Register
Diagnosis
MC33789
Satellite Sensor
LINE_MODE,
LINE_ENABLE
-
Comment
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 it’s initialization data, and the firmware must handle
this data to ensure the sensor is operating correctly.
4.1.9.1
LIN Physical Layer
Device
Function
Config Register
Diagnosis
MC33789
LIN physical layer
LIN_CONFIG
-
Comment
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Freescale Semiconductor
Function Description
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 raw Manchester encoded data from a satellite sensor to be monitored on the LIN output
pin, but this is only for the debug operation.
4.1.9.2
Lamp Driver
Device
Function
Config Register
Diagnosis
MC33789
Lamp driver
GPOn_CTL
GPOn_CTL
Comment
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.
4.1.9.3
Diagnostics
Device
Function
Config Register
Diagnosis
MC33789
Diagnostics
-
STATUS,
AI_CONTROL
Comment
The firmware can monitor the operation of the main ASIC through the STATUS and AI_CONTROL registers.
4.2
MMA6801QR2 – Local ECU Acceleration Sensor
The local ECU acceleration sensor is a dual channel device which also includes a safing block. At start up, configuration, offset
cancellation, and self test of the device, take place before the configuration is complete (’ENDINIT’ set) and the device goes into
normal operation.
4.2.1 Configuration - General
Device
Function
Config Register
Diagnosis
MMA6801QR2
Configuration
DEVCFG
-
Comment
The general configuration sets up the data format, whether offset monitoring is enabled, and the functionality of the ARM_X and
ARM_Y output pins. When configuration is complete, the ENDINIT bit is set and this locks out access to the configuration
registers
4.2.2 Configuration – Axis Operation
Device
Function
Config Register
Diagnosis
MMA6801QR2
Configuration
DEVCFG_X,
DEVCFG_Y
-
Comment
The axis operation configuration triggers self-test and selects one of the low pass filter options for each axis.
4.2.3 Configuration – Arming Operation
Device
Function
Config Register
Diagnosis
MMA6801QR2
Configuration
ARMCFG_X,
ARMCFG_Y
-
Comment
The arming operation configuration defines the arming pulse stretch period and the arming window, which has different
meanings, depending on which arming mode is configured.
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Function Description
4.2.4 Configuration – Arming Threshold
Device
Function
Config Register
Diagnosis
MMA6801QR2
Configuration
ARMT_XP, ARMT_XN
ARMT_YP, ARMT_YN
-
Comment
For each axis, both the positive and negative threshold can be set above which and when the arming window requirements are
met, the arm outputs will be set to active as defined in the arming operations register.
In the startup phase, the threshold can be set to such a level that when the self test deflection is triggered, the arming outputs
will become active. This can be used as part of the self-test at startup. After completion of the self test, thresholds should be set
back to the correct application values, and before the configuration is complete, by setting the ‘ENDINIT’ bit, after which no further
configuration changes can be made.
The complete startup and self-test procedure is described in the ARD specification (Airbag Reference Design).
Note that after the configuration is complete and the ‘ENDINIT’ bit is set, a CRC check of the configuration is carried out in the
background, which will lead to an error in the status register if a configuration bit flips.
4.2.5 Status
Device
Function
Config Register
Diagnosis
MMA6801QR2
Status
-
DEVSTAT
Comment
Internal errors are flagged in the DEVSTAT register.
4.3
MM33797 – Four Channel Squib Driver (FCS)
The ARD uses two FCS in cross-coupled mode to implement eight squib drivers.
The FCS is addressed using an 8-bit SPI interface over which commands and data are sent.
The only configuration possible is the time the device remains enabled after the fire enable (FEN1, FEN2) pins have been
activated. This is equivalent to the arming pulse stretch time applied to the safing output on both the system basis chip and the
local ECU sensor. Two commands are required to change this time – first is an unlock command and second is the programmed
time between 0 and 255 ms. Default is 0 ms.
Firing the squibs also requires two commands – the first arms one of the banks of drivers, the second turns on the required
switches. More than one switch can be turned on by a single command.
The majority of the commands relate to diagnostics of the FCS and the connected squibs. A full list of diagnostic commands is
available in the ARD specification (Airbag Reference Design).
4.4
MMA5xxxWR2 – High G Satellite Collision Sensor
No configuration of the MMA5xxxWR2 is possible. All configuration of the device is done off line prior to assembly in the system.
As soon as the device is switched on, it will begin an internal configuration and self test, and also sends initialization data, which
is received in the system basis chip and checked by the application. Once the device has completed sending the initialization
data, which concludes with an OK or NOK message, it enters normal operation and starts sending sensor data, either
autonomously if in asynchronous mode, or in response to SYNC pulses on the satellite sensor interface if in synchronous mode.
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Airbag Reference Demonstrator Firmware and Setup
Chapter 5 Airbag Reference Demonstrator Firmware and Setup
5.1
Airbag Reference Demonstrator Demo
The ECU is implemented on a single printed circuit board (PCB). Vehicle functions - in principal, satellite sensors, seat belt
switches, and warning lamp - are implemented on separate PCBs and mounted on a base Plexiglas plate. This set is placed on
rubber columns on the heavy aluminium base plate. Squibs are replaced by resistors with corresponding values to actual squibs.
Warning Lamp
Passenger Satellite Sensor
Rear Right Satellite Sensor
Driver Satellite Sensor
Rear Left Satellite Sensor
Rear Left Pretensioner SQUIB
Rear Right Pretensioner SQUIB
Rear Left SQUIB
Rear Right SQUIB
Driver SQUIB
Passenger SQUIB
Driver Pretensioner SQUIB
Passenger Pretensioner SQUIB
Power Supply Voltage
Seat Belt Buckle Sensors
Figure 5-1. Airbag Reference Demonstrator Demo Description
5.2
Warnings
The user should be aware of:
•
Operating power supply voltage from 6.0 to 20 V DC continuous
•
Nominal voltage 12 V DC (automotive battery)
•
Observe power supply voltage polarity. The devices have incorporated reverse battery protection, however, on-board
electrolytic capacitors may be damaged.
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Airbag Reference Demonstrator Firmware and Setup
5.3
Airbag Reference Demonstrator PCB Detail Description
RS232 Communication Port
OnBoard
LED1
OnBoard
LED2
BDM
Multi-link
Connector
Microcontroller
MC9S12XEG128
Energy
Reserve
Capacitors
Central
Accelerometer
MMA6801QR2
CAN Transceiver
Four Channel
Squib Driver #2
MC33797
Airbag
System
Basis
Chip
MC33789
Four Channel
Squib Driver #1
MC33797
Figure 5-2. ARD PCB Detail Description
5.4
Airbag Reference Demonstrator - GUI
FreeMASTER GUI application can work in 2 modes:
•
Debug Mode - GUI firmware together with GUI applications allow debug of the main ARD devices - MC33789 (Airbag
System Basis Chip), MC33797 (Four Channel Squib Driver), and MMA6801QR2 (Central Accelerometer). The device
registers are readable and configurable. At all times, the registers remain visible and can be monitored. This is intended
to aid engineers understand both the hardware and software routines.
•
Application Mode - application mode allows the users to view acceleration data from central and satellite
accelerometers. These numerical values are also plotted on a graph, which allows informative outlook to the
acceleration levels of all sensors. Deployment of squibs is simulated in this mode on a simple car model picture, using
pictures of both front and side deployments.
5.4.1 Firmware downloading - GUI version
When using the Code Warrior Development Studio S12(X) first time, install the Code Warrior IDE from the Freescale web page.
1. From CD open Code Warrior project file:
“\ARD_Firmwares\AirbagReferenceDesign_GUIFirmware\ard_gui_middle\ard_gui_middle.mcp”.
2. Connect the DC power supply 12 V. Observe polarity: red is positive, blue or black is negative.
3. Connect attached P&E micro debugger to J11 connector on the ARD main board and plug the USB cable to the PC
USB port.
4. Press function key F5 or go to “Project” and select “Debug”.
5. After finish of the downloading, unplug P&E micro debugger from the J11 port.
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Airbag Reference Demonstrator Firmware and Setup
NOTE
This firmware is loaded into Airbag Reference Demonstrator Demo after delivery and
immediately ready for using with the FreeMASTER GUI application without doing steps
above.
5.4.2 Hardware and Software Setup
When using the FreeMASTER first time, install the FreeMASTER tool from the enclosed CD, as well as the USB drivers. If you
have already done this, proceed to point 5.
1. From the CD run file: FreeMASTER\FMASTERSW.exe and leave all steps as the default.
2. Connect the DC power supply 12 V. Observe polarity: red is positive, blue or black is negative.
3. Plug the USB cable to the PC USB port. On the screen bottom right-hand corner will appear the message: “Found New
Hardware”. Please install the USB drivers located in the enclosed CD, directory \USB_Driver. USB driver is installed
twice. Once itself USB driver and second virtual RS232 COM port.
4. PC desktop, mouse right click the icon “My computer” and select “Properties”. The “System Properties” window will
open. Select the tab “Hardware” and then click on the “Device Manager” button. In a new window, expand the “Ports
(COM & LPT)”. If you have installed the USB drivers properly, the virtual COM ports will be listed, e.g. “USB Serial Port
(COMx)”. The PC assignees COMx port number. Note the port number used for FreeMASTER control pages
configuration.
5. Copy folder “AirbagReferenceDesign_GUI\” from the CD to your local hard drive. You will be able to save the
FreeMASTER configuration.
6. Open the Airbag Reference Demonstrator FreeMASTER control page.
7. “\ARD_GUI\MiddleARD_FreeMASTER.pmp”.
8. Immediately after opening, a message box may appears:
Click OK and proceed steps as follows.
1. Configure the COM port number and COM port speed 38400Bd, menu “Project\Options...”, the tab “Comm”. Write
proper serial communication port COMx (see bullet 4).
2. Open “File\Start communication” to establish the connection.
3. In case you do not execute mentioned steps properly, the message depicted in point 7 appears. The error sources
could be:
4. The ARD demo has no power.
5. COM ports are not assigned correctly.
6. Press Ctrl+S to save your settings.
5.4.3 GUI Demonstration
5.4.3.1
Debug mode
Parameters of the devices MC33789, MC33797, or MMA6801QR2, can be arbitrarily changed. Parameters are sent to the
selected device after the button press “Send Parameters To Reference Board“. All meaningful device registers are shown in the
registry table “Command Responses Table” at the bottom of the each device page. For each cell in this table, a tool-tip help is
available. Just place the mouse cursor over the cell to see descriptions of the selected register (see example page Figure 5-3).
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Airbag Reference Demonstrator Firmware and Setup
Figure 5-3. FreeMASTER Debug Page for the MC33789 Device
NOTE
After starting the watchdog refresh (Watchdog -> Enable), parameters “Safing Thresholds”
and “Dwell Extensions” in MC33789 can not be changed.
5.4.3.2
Application Mode
This simple ARD application mode allows to (see Figure 5-4):
•
View acceleration data from central and satellite accelerometers. These numerical values are displayed in points where
sensors should be placed inside the car.
•
View acceleration data plotted on a graph, which allows informative outlook to the acceleration levels of all sensors and
a simple car model simulation of the both front and side collisions. Plotted data is only informative, since transferred
data from sensors is averaged for illustration of ARD functionality only.
•
Simulate deployment of an airbag when the acceleration data reaches the threshold values. These thresholds are set
to very low limits, so the soft hit to sensor place by fingers or by rubber hand tool cause relevant airbags “deployment”.
This deployment is shown as inflated bags picture in a place where the “collision” occurred. Any “collision” at the driver
or passenger place causes inflation of two front airbags. Impact from left side causes inflation of the left side airbags,
and from right side causes deployment of the right sides airbags. Anytime after deployment, simulation is possible to
reset an inflated bag or bags by pressing button “Reset Deployed Airbags”.
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Airbag Reference Demonstrator Firmware and Setup
Figure 5-4. FreeMASTER Application Mode
NOTE
In this GUI mode during simulated airbags “deployment”, the relevant squibs drivers are not
activated.
5.5
Airbag Reference Demonstrator - “Application”
GUI firmware was designed specifically for communication with the GUI, but firmware uses the same API and low level drivers,
as the version described in this chapter, which is intended to demonstrate the functionality of the hardware in an application
environment.
The ARD application demonstrator firmware goes through the phases as indicated in Figure 5-5.
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Airbag Reference Demonstrator Firmware and Setup
Figure 5-5. Flowchart of the “Application Demonstrator“
Firmware has been divided into GUI firmware as described in 5.4, “Airbag Reference Demonstrator - GUI, and the real firmware
described in this chapter for keeping the readability of the C code, and also to allow full access to each analog device and its
registers in the GUI mode.
5.5.1 Firmware Downloading - “Application Demonstrator”
When using the Code Warrior Development Studio S12(X) for the first time, install the Code Warrior IDE from the Freescale web
page.
1. From the CD, open the Code Warrior project file:
“\ARD_Firmwares\AirbagReferenceDesign_Firmware\ard_application_middle\ard_application_middle.mcp”.
2. Connect the DC power supply 12 V. Observe polarity: red is positive, blue or black is negative.
3. Connect the attached P&E micro debugger to the J11 connector on the ARD main board, and plug the USB cable into
the PC USB port.
4. Press function key F5, or go to “Project” and select “Debug”.
5. After finishing the download, unplug the P&Emicro debugger from the J11 port.
NOTE
This firmware is NOT loaded into Airbag Reference Demonstrator Demo after delivery, and
for this ARD functionality, it is necessary to do all the above steps.
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Airbag Reference Demonstrator Firmware and Setup
5.5.2 Airbag Reference Demonstrator - “Application”
This real ARD application demonstrator allows simple user friendly verification of the functionality. Threshold values for initiation
of the airbag deployment are set at very low level limits, so simulation can take place without major car collision impact. Just a
soft hit to the sensor place by a finger, or by a rubber tool cause relevant airbag “deployment”.
All ARD SW processes work in real time - reading acceleration values, evaluation and deployment of the squib drivers. This ARD
application works independently without communication with the GUI. Evaluation of a collision is indicated only by RED or
YELLOW on-board LEDs on the main ECU board.
Lighting up the yellow LED means that impact occurred from the left or right rear side, lighting of the red denotes the collision
occurred from front side. Both LEDs switched on it means that the collision occurred from front and also from left or right rear side.
In this demonstrator mode, the relevant squibs (represented by equivalent resistors) are fired, means the firing current flows
through resistors, representing the actual airbag squibs.
For a collision simulation (see Figure 5-6):
•
hit the rear left sensor place => on-board YELLOW LED turns on
•
hit the rear left sensor place => on-board YELLOW LED turns on
•
hit the driver or passenger sensor place => on-board RED LED turns on
Simultaneously with on-board LEDs, the warning lamp is also turned on.
NOTE
Keep in mind that in case of a disconnection of the main supply voltage source (possible
automotive battery), the whole system is still powered by reserve capacitors in the Autarky
mode (roughly for 10 seconds), so it is possible to disconnect the power supply and still
operate the demonstrator.
After the power disconnection, please wait before turning off all on-board LEDs, and then
reconnecting the power supply.
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Airbag Reference Demonstrator Firmware and Setup
Hitting this point (passenger) causes
FRONT DEPLOYMENT
Hitting this point (driver) causes
FRONT DEPLOYMENT
Hitting this point causes
REAR RIGHT DEPLYOMENT
Yellow LED
Red LED
Hitting this point causes
REAR LEFT DEPLYOMENT
Figure 5-6. Demonstration of the Airbag Application
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Software - Boot Assist Module
Chapter 6 Software - Boot Assist Module
6.1
Boot Assist Module (BAM)
The Boost Assist Module controls start up of the demonstrator. During start up of the system, the power supply chain (boost
converter, buck converter, and linear regulator) starts automatically once the input to ASBC device has exceeded 5.2 V for more
than 1.0 ms. Once stabilized, system RESET is released, allowing the microcontroller to start operating.
Once operating, the microcontroller can continue with the start up process. The microcontroller must turn on the charging of the
main energy reserve capacitor and satellite sensors (if present), configure acceleration thresholds for the safing block in central
accelerometer, and run a complete diagnostic check of the system before turning off the driver warning lamp.
Once the driver warning lamp has been switched off, the system is considered ‘ARMED’ and able to fire squibs, if no system fault
is found prior to a collision, this leads to the warning lamp being switched on again.
Figure 6-1. Boot Startup Architecture
6.1.1 Example of the BAM source code
This example of the BAM consists of initializing of all the devices on the main ECU board. Each device calls for one standalone
initialization API function, and other required features are configured by separate driver functions.
Checking if devices work properly are performed. If all required parameters are set correctly, no device reports any internal error,
and if all device tests and their peripherals are without error, the ARD application continues the BOM phase. Otherwise, the
systems halts and does not continue its operation.
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Software - Boot Assist Module
/* Init Airbag System Basis Chip */
ret_asbc = Asbc_Init(ARD_SPI_ASBC, &Asbc_Config[0]); /* initialization of the ASBC device MC33789 */
if(ret_asbc == ASBC_OK){
/* Setup ASBC device */
Gpt_Enable(); /* enable ASBC watchdog refresh - enable RTI interrupt */
ret_asbc = Asbc_SetSafingMode(ARD_SPI_ASBC, ASBC_SAFING_CHANGE_TO_SAFING_MODE,
ASBC_SAFING_TEST_DIS, ASBC_SAFING_ARM_OUT_0); /* set ASBC device to the
Safing mode, disable FEN/FDIS arming testing mode */
if(ret_asbc == ASBC_NOT_OK) Ard_Status = ARD_ERROR; /* ASBC device is not in SAFING mode */
ret_asbc = Asbc_SetVregMode(ARD_SPI_ASBC, &Asbc_VregConfig[0]); /* configure voltage regulators */
ret_asbc = Asbc_SetGpo(ARD_SPI_ASBC, ASBC_GPO_1, ASBC_GPO_DC_66_7, ASBC_GPO_LS_DRIVER); /* driver
warning lamp set ON (duty cycle 66,7%) */
ret_asbc = Asbc_SetGpo(ARD_SPI_ASBC, ASBC_GPO_2, ASBC_GPO_DC_OFF, ASBC_GPO_HS_DRIVER); /* unused
output */
ret_asbc = Asbc_SetLinMode(ARD_SPI_ASBC, &Asbc_LinConfig[0]); /* LIN physical layer configuration */
ret_asbc = Asbc_SetPsi5Mode(ARD_SPI_ASBC, &Asbc_Psi5Config[1]); /* configure PSI5 interface - turn satellite
sensors interface OFF */
/* Check ASBC device */
/* Read System Basis Chip statuses */
Asbc_Status.Asbc_StatFullEnable = ASBC_STAT_FULL_EN; /* truncated status of the ASBC device */
ret_asbc = Asbc_GetStatus(ARD_SPI_ASBC, &Asbc_Status); /* common status of the ASBC device */
ret_asbc = Asbc_GetLinStatus(ARD_SPI_ASBC, &Asbc_LinStatus); /* get LIN physical layer settings */
ret_asbc = Asbc_GetPsi5Status(ARD_SPI_ASBC, &Asbc_Psi5Status); /* the status of the ASBC PSI5 interface */
ret_asbc = Asbc_GetVregStatus(ARD_SPI_ASBC, ASBC_VREG_ESR_DIS, &Asbc_VregStatus); /* read status of the
ASBC voltage regulators and measure state of the Energy Reserve capacitor */
}else{
Ard_Status = ARD_ERROR; /* Airbag System Basis Chip initialization failed */
}
/* Init Central Accelerometer */
if(Ard_Status != ARD_ERROR){ /* if the system basis chip started without error */
ret_acc = Acc_Init(ARD_SPI_ACC, &Acc_Config[0]); /* setup central accelerator device */
ret_acc = Acc_GetStatus(ARD_SPI_ACC, &Acc_Status); /* read the complete statuses of the ACC device */
if(ret_acc != ACC_OK){ /* initalization or get ACC status failed */
Ard_Status = ARD_ERROR; /* Central Accelerometer initialization failed */
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Software - Boot Assist Module
}
}
/* Init SQUIB drivers */
if(Ard_Status != ARD_ERROR){ /* if the ASBC and ACC started without error */
ret_squib = Squib_Init(ARD_SPI_SQUIB1); /* the function initializes the SQUIB1 driver - device MC33797 */
if(ret_squib == SQB_OK){ /* if SQUIB1 initialized without any errors */
ret_squib = Squib_GetStatus(ARD_SPI_SQUIB1, &Sqb1_Status); /* get status of the 1A, 1B, 2A, 2B of the SQUIB1 */
if(ret_squib == SQB_OK){ /* if return from the Squib_GetStatus are without error */
ret_squib = Squib_Init(ARD_SPI_SQUIB2); /* the function initializes the SQUIB2 driver - device MC33797 */
if(ret_squib == SQB_OK){ /* if SQUIB2 initialized without any errors */
ret_squib = Squib_GetStatus(ARD_SPI_SQUIB2, &Sqb2_Status); /* get status of the 1A, 1B, 2A, 2B of the SQUIB2 */
if(ret_squib != SQB_OK){ /* if error return from the Squib_GetStatus */
Ard_Status = ARD_ERROR;
}
}else Ard_Status = ARD_ERROR;
}else Ard_Status = ARD_ERROR;
}else Ard_Status = ARD_ERROR;
}
if(Ard_Status != ARD_ERROR){ /* if SQUIBs devices started without error - check all SQUIB1 and SQUIB2 parameters */
/* SQUIB1 short to GND or to BATTERY */
if(Sqb1_Status.Squib_1AShBatt == SQB_SH_TO_BATT_FAULT) Ard_Status = ARD_ERROR;
if(Sqb1_Status.Squib_1AShGnd == SQB_SH_TO_GND_FAULT) Ard_Status = ARD_ERROR;
if(Sqb1_Status.Squib_1BShBatt == SQB_SH_TO_BATT_FAULT) Ard_Status = ARD_ERROR;
….
…
…
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Software - Basic Operating System
Chapter 7 Software - Basic Operating System
Once the start up phase has completed and the warning lamp has been switched off, the system is ready to operate normally, at
which time the airbag control algorithm will be running.
The control algorithm consists of three phases:
•
Acquisition Phase – sensor data is acquired from all on-board and remote sensors
•
Decision Phase – the decision is taken based on the available sensor data, and whether an airbag or airbags need to
be fired
•
Deployment Phase – if the decision is taken to fire airbags, the relevant squib drivers must be armed and fired in
sequence
In normal operation mode, diagnostics and system status recording should operate. Period diagnostic checks should be carried
out in a fixed sequence, to ensure that over a period equivalent to the time for system status updates in EEPROM to be made,
a complete diagnostic check can be made.
7.1
Acquisition Phase
In the acquisition phase, the microcontroller reads the sensor data required to enable a deployment decision to be taken.
At the same time the microcontroller reads the sensor data, the safing block in MC33789 is loaded with the same sensor data
through the SPI-monitor block. An independent decision can then be taken by the MC33789 safing block based on the sensor
data whether to enable the squib drivers and allow deployment of the required airbag or airbags, which will be done under control
of the application on the microcontroller.
There is a fixed order in which data has to be read into the MC33789 safing block, even if a sensor in the sequence is missing
or has failed. Therefore, a dummy read of sensor data has to be made to maintain the sequence. For example, a read of a logical
channel equivalent to a non-implemented channel in the PSI5 block, i.e. any fourth channel of a PSI5 interface will result in a
response which contains the correct sequence number but not valid data.
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Software - Basic Operating System
Figure 7-1. Acquisition Phase Flowchart
7.1.1 Source code of the Acquisition phase
Complete Acquisition phase including reading acceleration data from the main inboard sensor and satellite sensors is described
in the following source code.
/* Read acceleration data from central accelerometer and from satellite sensors */
/* Synchronization pulse starts */
SyncPulseStart(); /* rising edge of the SATSYNC pulse */
/* Acquisition Sequence #0 and #1 - read central accelerometer X-axis and Y-axis data */
ret_acc = Acc_GetAccelData(ARD_SPI_ACC, ACC_X_OFFSETCANCEL_SIGNED_ARMENABLE,
ACC_Y_OFFSETCANCEL_SIGNED_ARMENABLE, &AccelerationData); /* read X and Y axis
accelerometer moving value and error status */
/* Acquisition Sequence #2 - dummy reading (PSI5 LC = 0011) */
Asbc_ReadSensor(ARD_SPI_ASBC, ASBC_SEQUENCE_IDENTIFIER_02, ASBC_LOG_PSI5_CHAN1_DUMMY,
&SensorDummy, SensStatus); /* dummy reading */
/* Acquisition Sequence #3 - dummy reading (PSI5 LC = 0111) */
Asbc_ReadSensor(ARD_SPI_ASBC, ASBC_SEQUENCE_IDENTIFIER_03, ASBC_LOG_PSI5_CHAN2_DUMMY,
&SensorDummy, SensStatus); /* dummy reading */
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Software - Basic Operating System
/* Acquisition Sequence #4 - read front-left satellite (PSI5 LC = 0000) */
Asbc_ReadSensor(ARD_SPI_ASBC, ASBC_SEQUENCE_IDENTIFIER_04, ASBC_LOG_PSI5_CHAN1_SLOT1,
&SensorData_Driver, SensStatus); /* acceleration data from front left satellite sensor */
/* Acquisition Sequence #5 - read front-right satellite (PSI5 LC = 0100) */
Asbc_ReadSensor(ARD_SPI_ASBC, ASBC_SEQUENCE_IDENTIFIER_05, ASBC_LOG_PSI5_CHAN2_SLOT1,
&SensorData_Passenger, SensStatus); /* acceleration data from front right satellite sensor */
/* Acquisition Sequence #6 - read side-right satellite (PSI5 LC = 1000) */
Asbc_ReadSensor(ARD_SPI_ASBC, ASBC_SEQUENCE_IDENTIFIER_06, ASBC_LOG_PSI5_CHAN3_SLOT1,
&SensorData_RearRight, SensStatus); /* acceleration data from rear right satellite sensor */
/* Acquisition Sequence #7 - read side-left satellite (PSI5 LC = 1100) */
Asbc_ReadSensor(ARD_SPI_ASBC, ASBC_SEQUENCE_IDENTIFIER_07, ASBC_LOG_PSI5_CHAN4_SLOT1,
&SensorData_RearLeft, SensStatus); /* acceleration data from rear left satellite sensor */
/* Complete synchronization pulse */
SyncPulseEnd(); /* falling edge of the SATSYNC pulse */
/* Read ASBC Safing status */
Asbc_Status.Asbc_StatFullEnable = ASBC_STAT_FULL_DIS; /* truncated status of the ASBC device */
ret_asbc = Asbc_GetStatus(ARD_SPI_ASBC, &Asbc_Status); /* common status of the ASBC device */
/* Check correct number of the valid data */
if(Asbc_Status.Asbc_SafingDataCount == 6){ /* check correct number of the valid data - expected number is "6" */
/* 1. reading is from central accelerometer X-axis */
/* 2. reading is from central accelerometer Y-axis */
/* 3. reading is from front left satellite sensor */
/* 4. reading is from front right satellite sensor */
/* 5. reading is from side right satellite sensor */
/* 6. reading is from side left satellite sensor */
DataErrorCounter = 0; /* clear data invalid counter */
Ard_Status = ARD_DECISION; /* go to Decision Phase */
}else{ /* Safing counter parameter Asbc_SafingDataCount contains a different number than expected */
DataErrorCounter = DataErrorCounter + 1; /* increment data invalid counter */
if(DataErrorCounter > ARD_DATA_INVALID_COUNT_LIMIT){ /* if the number of the invalid data exceed limit */
Ard_Status = ARD_ERROR; /* reading attempts from sensors ended with failure (warning lamp ON and syst halt) */
}else{ /* invalid counter did not exceed limit value */
Ard_Status = ARD_ACQUISITION; /* system will stay here in the Acquisition Phase */
}
}
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Software - Basic Operating System
7.2
Decision Phase
In the decision phase, the microcontroller interprets the sensor data read during the acquisition phase to calculate which, if any,
squibs need to be fired. The decision phase follows the acquisition phase as long as the DATA_VALID count in the acquisition
phase is correct.
The decision whether to fire a squib is always based on at least two sensor readings. Where two sensor readings confirm that a
deployment is required in three successive decision phases, a flag is set which will trigger the deployment, in the deployment
phase. If no deployment is necessary, the system will have time before the next acquisition phase starts to run diagnostic tests.
NOTE
The example flowchart in Figure 7-2 demonstrates a simple decision phase that is intended
only to demonstrate the functionality of the reference demonstrator hardware, and is not
intended to represent a true airbag application.
FRONT DECISION
source code example is
shown in chapter 7.1.2.1
Figure 7-2. Decision Phase Flowchart
7.2.1 Example of the API Source Code Used in Decision Phase - Front Decision
An example of the SW implementation of the front decision is described in the following example. Any exceeding of the threshold
values at driver or passenger place causes transition to the deployment phase and deployment of two front airbags. Decisions
for the rear passengers are done in the same way.
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Software - Basic Operating System
/* FRONT DECISION */
if(AccelerationData.AccelDataX > ACC_X_ARM_THRESHOLD){ /* if data from accelerometer (X-axis) exceed thresholds */
/* FRONT RIGHT DECISION */
if(SensorData_Passenger > Asbc_Config[0].Asbc_SafingThreshold2){ /* data from front right sensor exceed Threshold2 */
FrontRightCounter = FrontRightCounter + 1; /* increment number of the exceeded acceleration thresholds from the front
right satellite sensor and from the central accelerometer */
if(FrontRightCounter > ARD_DECISION_COUNT_LIMIT){ /* number of the exceeded accel values exceed counter limit */
PassengerDeploy = DEPLOY_PASSENGER; /* passenger squib deployment required */
}
}else{ /* no thresholds were exceeded */
FrontRightCounter = 0; /* clear front right counter */
PassengerDeploy = NO_DEPLOY; /* reset deployment flag to default state */
}
/* FRONT LEFT DECISION */
if(SensorData_Driver > Asbc_Config[0].Asbc_SafingThreshold2){ /* data from front left sensor exceed Threshold2 */
FrontLeftCounter = FrontLeftCounter + 1; /* increment number of the exceeded acceleration thresholds from the front
left satellite sensor and from the central accelerometer */
if(FrontLeftCounter > ARD_DECISION_COUNT_LIMIT){ /* number of the exceeded accel values exceed counter limit */
DriverDeploy = DEPLOY_DRIVER; /* driver squib deployment required */
}
}else{ /* no thresholds were exceeded */
FrontLeftCounter = 0; /* clear front left counter */
DriverDeploy = NO_DEPLOY; /* reset deployment flag to default state */
}
}
7.3
Deployment Phase
The deployment phase is entered if the application has decided that at least one airbag needs to be deployed. Typically, more
than one deployment is needed in any collision – any airbag deployment will also be backed up with at least one seatbelt
pre-tensioner activation. Each of the four decisions taken in the decision phase is linked directly to an airbag and a related
seatbelt pre-tensioner. Prior to activation of the pre-tensioners, the condition of the seatbelt switch is checked using the DC
sensor on the MC33789.
As in a real airbag application, after the deployment phase, the system should return to the acquisition phase to attempt to deal
with a second collision, except in the case that all airbags and pre-tensioners have been deployed already.
Note: the example flowchart here demonstrates a simple deployment phase intended only to demonstrate the functionality of the
reference demonstrator hardware, and is not intended to represent a true airbag application.
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Software - Basic Operating System
DRIVER
SEAT
DEPLOYMENT
source code example is described in
the Deployment Phase chapter
Figure 7-3. Deployment phase Flowchart
7.3.1 Example of the API Source Code Used in Deployment Phase
This source code example relates to the deployment of the driver seat. The other three seats would be driven by a similar code
sequence. If deployment is required, based on the verdict from a previous decision phase. The pre-tensioner for the seat belt is
deployed first before deployment of the main driver’s airbag.
Commands to switch Low-FET and High-FET switches are sent to the appropriate SQUIB DRIVER IC. The low side squib driver
must be activated prior to activating the high side squib driver.
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Software - Basic Operating System
/* DEPLOY DRIVER SEAT */
if((DriverDeploy == DEPLOY_DRIVER) && (GetPort(ARM)) && (GetPort(ARM_X))){ /* driver squib deployment required? */
/* Deploy driver pre-tensioner (if the driver seat belt is engaged) */
if(DriverBuckle == TRUE){ /* the driver seat belt is engaged */
/* Deploy driver pre-tensioner (the SQUIB2(LO_1B) driver must be activated prior the SQUIB1(HI_1B) driver) */
ret_squib = Squib_Fire(ARD_SPI_SQUIB2, CMD_FIRE_1BLS); /* switch ON 1B Low Side on the SQUIB2 */
if(ret_squib == SQB_NOT_OK) Ard_Status = ARD_ERROR; /* if any error occures */
ret_squib = Squib_Fire(ARD_SPI_SQUIB1, CMD_FIRE_1BHS); /* switch ON 1B High Side on the SQUIB1 */
if(ret_squib == SQB_NOT_OK) Ard_Status = ARD_ERROR; /* if any error occures */
}
/* Deploy driver airbag = the SQUIB2(LO_1A) driver must be activated prior to activating the SQUIB1(HI_1A) driver */
ret_squib = Squib_Fire(ARD_SPI_SQUIB2, CMD_FIRE_1ALS); /* switch ON 1A Low Side on the SQUIB2 */
if(ret_squib == SQB_NOT_OK) Ard_Status = ARD_ERROR; /* if any error occures */
ret_squib = Squib_Fire(ARD_SPI_SQUIB1, CMD_FIRE_1AHS); /* switch ON 1A High Side on the SQUIB1 */
if(ret_squib == SQB_NOT_OK) Ard_Status = ARD_ERROR; /* if any error occures */
DriverDeploy = DRIVER_DEPLOYED; /* set driver airbag status - driver airbag deployed */
}
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SW Concept
Appendix A
SW Concept
ARD software is built on basic low level MCU drivers, which provide access to the modules ADC, GPIO, EEPROM, GPT. etc. in
the microprocessor, and provide all necessary MCU functions. The upper software layer contains drivers for all main ARD devices
- Main Airbag ASIC MC33789 (ASBC Driver), Central Accelerometer MMA6801QR2 (ACC Driver), and Four Channel Squib
Driver MC33797 (SQUIB Driver). These drivers have an MCU independent API, which means no modification of ASBC, SQUIB
or ACC drivers are needed for all MCU derivatives (8/16/32b).
Figure 7-4. SW Design concept
A.1
Airbag System Basis Chip SW Driver
The ASBC driver is written as a separate software module. The main advantage is full HW abstraction and API independence in
used MCU family. The driver API covers the entire functionality of the ASBC device, which means all registers can be
configured/read using API functions.
The ASBC Driver is dependent on the COM layer (basic SPI communication) and on the GPT driver (General Purpose Timer),
which provides timing functions that are needed primarily for watchdog control.
Figure 7-5. Airbag System Basis Chip SW Driver Concept
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SW Concept
Table 7-1. Airbag System Basis Chip SW Driver API
Function Name
Function Parameters
Return Type
Function Description
Asbc_Init
Spi_Channel [in]
*Config [in]
Asbc_ReturnType
Initialize the Airbag System Basis Chip and returns the
confirmation of initialization. Multiple initialization
configuration is supported via the Config parameter.
Asbc_GetStatus
Spi_Channel [in]
*Status [out]
Asbc_ReturnType
Return the status of the ASBC. Only the general statuses
are reported via this service.
Asbc_SetAnlMuxSourc Spi_Channel [in]
e
Source [in]
Asbc_ReturnType
Allow to change the analog parameter which is connected
to the AOUT output.
Asbc_SetDcsMuxSour Spi_Channel [in]
ce
Source [in]
Voltage [in]
Asbc_ReturnType
Determines which DC sensor input channel shell be
connected for diagnostic output.
Asbc_SetVregMode
Spi_Channel [in]
*Config [in]
Asbc_ReturnType
Set the ASBC Voltage regulator. Various configurations of
voltage regulators are supported via the Asbc_VregConfig
container.
Asbc_GetVregStatus
Spi_Channel [in]
*Status [out]
Asbc_ReturnType
Return the status of the ASBC Voltage regulators. This
also contains the Boost and Buck statuses.
Asbc_SetPsi5Mode
Spi_Channel [in]
*Config [in]
Asbc_ReturnType
Set the ASBC PSI5 four satellite sensor interface. Various
configurations of PSI5 interface are supported via the
Asbc_Psi5Config container.
Asbc_GetPsi5Status
Spi_Channel [in]
*Status [out]
Asbc_ReturnType
Return the status of the ASBC PSI5 interface.
Asbc_SetLinMode
Spi_Channel [in]
*Config [in]
Asbc_ReturnType
Set the ASBC LIN transceiver mode. Via the
Asbc_LinConfig configuration container various
configurations are supported.
Asbc_GetLinStatus
Spi_Channel [in]
*Status [out]
Asbc_ReturnType
Return the ASBC LIN transceiver status.
Asbc_SetGpo
Spi_Channel [in]
GpoChannel [in]
GpoPwmDutyCycle [in]
GpoDriverConfig [in]
Asbc_ReturnType
Set the ASBC output channel mode. Various configuration
for each output channel are supported via the
Asbc_GpoDriverConfig configuration container.
Asbc_GetGpoStatus
Spi_Channel [in]
GpoChannel [in]
*Status [out]
Asbc_ReturnType
Return the ASBC output channel status. This includes the
high/low side selection, thermal shutdown and the voltage
level.
Asbc_ReadSensor
Spi_Channel [in]
SequenceIdentifier [in]
LogicalChannel [in]
Asbc_ReturnType
This function provide sensor request/response to retrieve
sensor data from satellite interface block.
Asbc_FeedWatchdog
Spi_Channel [in]
WD_Polarity [in]
Asbc_ReturnType
Update the ASBC Watchdog. A successful watchdog
refresh is a SPI command (high), following another SPI
command (low).
Asbc_ProgramCmd
Spi_Channel [in]
Command [in]
Data [in]
SpiResponse [out]
Asbc_ReturnType
Send any ASBC command to the device and read its
response.
A.2
ASBC API parameters detail descriptions
Brief description of input and output API parameters is in the following paragraphs. Descriptions contains only a verbal description
of the parameter. Values which can variable acquired is described in the header file ASBC.h.
Parameters of the Asbc_Init API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Config (Asbc_ConfigType) - input configuration structure:
— Asbc_SafingThreshold0 - 8 bits safing 0 threshold value
— Asbc_SafingDwellExt0 - extension of the arming pulse width (either 255 ms or 2.0 s) for threshold0
— Asbc_SafingThreshold1 - 8 bits safing 1 threshold value
— Asbc_SafingDwellExt1 - extension of the arming pulse width (either 255 ms or 2.0 s) for threshold1
— Asbc_SafingThreshold2 - 8 bits safing 2 threshold value
— Asbc_SafingDwellExt2 - extension of the arming pulse width (either 255 ms or 2.0 s) for threshold2
— Asbc_SafingThreshold3 - 8 bits safing 3 threshold value
— Asbc_SafingDwellExt3 - extension of the arming pulse width (either 255 ms or 2.0 s) for threshold3
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Asbc_SafingThreshold4 - 8 bits safing 4 threshold value
Asbc_SafingDwellExt4 - extension of the arming pulse width (either 255 ms or 2.0 s) for threshold4
Asbc_SafingThreshold5 - 8 bits safing 5 threshold value
Asbc_SafingDwellExt5 - extension of the arming pulse width (either 255 ms or 2.0 s) for threshold5
Asbc_SafingThreshold6 - 8 bits safing 6 threshold value
Asbc_SafingDwellExt6 - extension of the arming pulse width (either 255 ms or 2.0 s) for threshold6
Asbc_SafingThreshold7 - 8 bits safing 7 threshold value
Asbc_SafingDwellExt7 - extension of the arming pulse width (either 255 ms or 2.0 s) for threshold7
Parameters of the Asbc_GetStatus API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Status (Asbc_StatusType) output status structure containing the common status of the ASBC device:
— Asbc_VregSyncSuppOverTemp - Sync supply over-temperature error
— Asbc_VregSensRegulOverTemp - DC sensor regulator over-temperature error
— Asbc_VregBoostOverTemp - Boost supply over-temperature error
— Asbc_VregIgnState
— Asbc_WakeupPinState - wake-up pin state
— Asbc_WdogState - watchdog state
— Asbc_WdogErrStatus - watchdog error status
— Asbc_SafingSequenceErr - safing sequence error
— Asbc_SafingOffsetErr - safing offset error
— Asbc_SafingMode - safing mode status
— Asbc_SafingDataCount - number of digital sensor messages received with valid sensor data
— Safing threshold settings - these parameters are returned the same values as described in the initialization
function ASBC_Init
Parameters of the Asbc_SetAnlMuxSource API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Source (Asbc_AnlMuxSourceType) input parameter - analog source which will be connected to the MUX input
Parameters of the Asbc_SetDcsMuxSource API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Source (Asbc_DcsMuxSourceType) input parameter - sensor channel selection determines which DC sensor input
shall be connected for diagnostics output
•
Voltage (Asbc_DcsMuxSourceType) input parameter - bias voltage selection determines which regulated voltage shall
be used as a bias supply on the DC sensor output stage for diagnostics
Parameters of the Asbc_SetSafingMode API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
SafingMode (Asbc_SafingModeRequestType) input parameter - safing mode request
•
SafingTestEnable (Asbc_SafingTestEnableType) input parameter - safing test enable
•
SafingLevel (Asbc_SafingLevelType) input parameter - arming output level
Parameters of the Asbc_SetVregMode API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Config (Asbc_VregConfigType) input configuration parameter - configuration of the ASBC voltage regulator:
— Asbc_VregSyncSupply (Asbc_VregConfigType) input parameter - Sync supply control
— Asbc_VregBoost (Asbc_VregBoostType) input parameter - Boost regulator control
— Asbc_VregBuck (Asbc_VregBuckType) input parameter - Buck regulator control
— Asbc_VregEnergyReserve (Asbc_VregEnergyReserveType) input parameter - energy reserve control
Parameters of the Asbc_GetVregStatus API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
VregEnergyReserveTest (Asbc_VregEnergyReserveTestType) input parameter - energy reserve test diagnostic
control
•
Status (Asbc_VregStatusType) output structure containing the status of the ASBC voltage regulators:
— Asbc_VregBoost (Asbc_VregStatBoostType) - report boost voltage less/greater than threshold (~80% of target)
— Asbc_VregChargDischarFault (Asbc_VregStatChargDischarFaultType) - CER charge/discharge switch failure
status
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Asbc_VregSyncSupply (Asbc_VregSyncSupplyType) - Sync supply status
Asbc_VregBoostEnable (Asbc_VregBoostType) - Boost regulator status
Asbc_VregBuckEnable (Asbc_VregBuckType) - Buck regulator status
Asbc_VregEnergyReserve (Asbc_VregEnergyReserveType) - energy reserve status
Asbc_VregEnergyReserveValue (uint8) - energy reserve test diagnostic status
Parameters of the Asbc_SetPsi5Mode API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Config (Asbc_Psi5ConfigType) input configuration structure of the ASBC PSI5 interface:
— Asbc_PSI5Chann1Mode (Asbc_PSI5Chann1ModeType) - PSI5 channel 1 mode - Synchronous SATSYNC
(Steered Mode) or Synchronous TDM Mode
— Asbc_PSI5Chann1Enable (Asbc_PSI5Chann1EnableType) - PSI5 channel 1 enable/disable
— Asbc_PSI5Chann1SynPuls (Asbc_PSI5Chann1SynPulsType) - PSI5 channel 1 sync pulse enable/disable
— Asbc_PSI5Chann2Mode (Asbc_PSI5Chann2ModeType) - PSI5 channel 2 mode - Synchronous SATSYNC
(Steered Mode) or Synchronous TDM Mode
— Asbc_PSI5Chann2Enable (Asbc_PSI5Chann2EnableType) - PSI5 channel 2 enable/disable
— Asbc_PSI5Chann2SynPuls (Asbc_PSI5Chann2SynPulsType) - PSI5 channel 2 sync pulse enable/disable
— Asbc_PSI5Chann3Mode (Asbc_PSI5Chann3ModeType) - PSI5 channel 3 mode - Synchronous SATSYNC
(Steered Mode) or Synchronous TDM Mode
— Asbc_PSI5Chann3Enable (Asbc_PSI5Chann3EnableType) - PSI5 channel 3 enable/disable
— Asbc_PSI5Chann3SynPuls (Asbc_PSI5Chann3SynPulsType) - PSI5 channel 3 sync pulse enable/disable
— Asbc_PSI5Chann4Mode (Asbc_PSI5Chann4ModeType) - PSI5 channel 4 mode - Synchronous SATSYNC
(Steered Mode) or Synchronous TDM Mode
— Asbc_PSI5Chann4Enable (Asbc_PSI5Chann4EnableType) - PSI5 channel 4 enable/disable
— Asbc_PSI5Chann4SynPuls (Asbc_PSI5Chann4SynPulsType) - PSI5 channel 4 sync pulse enable/disable
Parameters of the Asbc_GetPsi5Status API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Status (Asbc_Psi5StatusType) output structure containing the status of the ASBC PSI5 interface: - returned parameters
are the same as is described in Asbc_SetPsi5Mode function above.
Parameters of the Asbc_SetLinMode API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Config (Asbc_LinConfigType) input configuration structure of the ASBC LIN bus interface:
— Asbc_LinSlewRate (Asbc_LinSlewRateType) - LIN slew rate selection
— Asbc_LinRXDMode (Asbc_LinRXDModeType) - RxD output function
— Asbc_LinRXOut (Asbc_LinRXOutType) - Rx output selection (for RxD satellite function)
Parameters of the Asbc_GetLinStatus API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Status (Asbc_LinStatusType) output structure containing the status of the ASBC LIN bus interface:
— Asbc_LinSlewRate (Asbc_LinSlewRateType) - LIN slew rate selection
— Asbc_LinRXDMode (Asbc_LinRXDModeType) - RxD output function
— Asbc_LinRXOut (Asbc_LinRXOutType) - Rx output selection (for RxD satellite function)
Parameters of the Asbc_SetGpo API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
GpoChannel (Asbc_GpoChannelType) - selected GPO pin
•
GpoPwmDutyCycle (Asbc_GpoPwmDutyCycleType) - output PWM duty cycle
•
GpoDriverConfig (Asbc_GpoDriverConfigType) - HS/LS driver configuration selection
Parameters of the Asbc_GetGpoStatus API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
GpoChannel (Asbc_GpoChannelType) - selected GPO pin
•
Status (Asbc_GpoStatusType) output structure containing the status of the selected output:
— Asbc_GpoDriverConfig - HS/LS driver configuration selection
— Asbc_GpoDriverOn13 - driver ON 1/3 VPWR comparator result
— Asbc_GpoDriverOn23 - driver ON 2/3 VPWR comparator result
— Asbc_GpoDriverOff13 - driver OFF 1/3 VPWR comparator result
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Asbc_GpoDriverOff23 - driver OFF 2/3 VPWR comparator result
Parameters of the Asbc_ReadSensor API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
SequenceIdentifier (Asbc_PSI5SequenceIdentifierType) - PSI5 sequence identifier (used for synchronizing samples)
•
LogicalChannel (Asbc_PSI5LogicalChannelType) - PSI5 logical channel selection
•
SensorData (uint16) - data from selected satellite sensor
•
SensorStatus (Asbc_SensorStatusType) - satellite sensor response status
Parameters of the Asbc_FeedWatchdog API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
WD_Polarity (Asbc_WdLevelType) - watchdog polarity value
Parameters of the Asbc_ProgramCmd API function:
•
Spi_Channel (Asbc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Command (Asbc_SpiChannelType) - non sensor command
•
Data (uint16) - data
•
SpiResponse (uint16) - response to the sent command
A.3
Central Accelerometer Driver
The ACC driver is created as a separate software module. The main advantage is full HW abstraction and API independence in
used MCU family. The driver API covers the entire functionality of the main accelerometer, which means all accelerometer
functionality can be controlled using API functions.
The ACC Driver is dependent on the COM layer (basic SPI communication), and on the GPIO driver (General Purpose
Input/Output), which provides basic functions for controlling input/output MCU pins.
Figure 7-6. Central Accelerometer SW driver concept
Table 7-2. Central Accelerometer SW driver API
Function Name
Function Parameters
Return Type
Acc_Init
Spi_Channel [in]
*Config [in]
Acc_ReturnType
Acc_GetStatus
Spi_Channel [in]
*Status [out]
Acc_ReturnType
Function Description
Initialize the central accelerometer device and
returns the confirmation of initialization. Multiple
initialization configuration is supported via the
Config parameter.
Return the whole status of the Mesquite
accelerometer device.
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Table 7-2. Central Accelerometer SW driver API
Function Name
Acc_GetAccelData
Acc_ProgramCmd
A.4
Function Parameters
Spi_Channel [in]
AccelCmdX [in]
AccelCmdY [in]
*Status [out]
Spi_Channel [in]
RegAddress [in]
Data [in]
SpiResponse [out]
Return Type
Function Description
Acc_ReturnType
Read the X and Y axis accelerometer moving
values and other necessary statuses.
Acc_ReturnType
Read/write independently any IC register.
ACC Parameters Detail Descriptions
A brief description of input and output API parameters is in the following paragraphs. Descriptions contain only a verbal
description of the parameter. Values which each variable acquires is described in the header file ACC.h.
Parameters of the Acc_Init API function:
•
Spi_Channel (Acc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Config (Acc_ConfigType) - input configuration structure:
— Acc_ConfSignData - this variable determines the format of acceleration data results
— Acc_OffsetMoni - offset monitor circuit enable/disable
— Acc_ArmOutput - mode of operation for the ARM_X/PCM_X and ARM_Y/PCM_Y pins
— Acc_XAxisSelfTest - enable or disable the self-test circuitry for X axis
— Acc_YAxisSelfTest - enable or disable the self-test circuitry for Y axis
— Acc_XLowPassFilter - the low pass filter selection bits independently select a low-pass filter for X axis
— Acc_YLowPassFilter - the low pass filter selection bits independently select a low-pass filter for Y axis
— Acc_XArmPulseStretch - pulse stretch time for X arming outputs
— Acc_YArmPulseStretch - pulse stretch time for Y arming outputs
— Acc_XArm_PosWin_CountLimit - X axis positive arming window size definitions or arming count limit definitions
function (depending on the state of the Acc_ArmOutput variable)
— Acc_YArm_PosWin_CountLimit - Y axis positive arming window size definitions or arming count limit definitions
function (depending on the state of the Acc_ArmOutput variable)
— Acc_XArm_NegWinSize - X axis negative arming window size definitions (meaning depend on the state of the
Acc_ArmOutput variable)
— Acc_YArm_NegWinSize - Y axis negative arming window size definitions (meaning depend on the state of the
Acc_ArmOutput variable)
— Acc_XArmPositiveThreshold - this value contain the X axis positive threshold to be used by the arming function
— Acc_YArmPositiveThreshold - this value contain the Y axis positive threshold to be used by the arming function
— Acc_XArmNegativeThreshold - this value contain the X axis negative thresholds to be used by the arming
function
— Acc_YArmNegativeThreshold - this value contain the Y axis negative thresholds to be used by the arming
function
Parameters of the Acc_GetStatus API function:
•
Spi_Channel (Acc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Status (Acc_StatusType) output status structure containing the complete status of the ACC device:
— Acc_SerialNumber - device serial number
— Acc_LotNumberHigh - device high lot number value
— Acc_LotNumberMidd - device midd lot number value
— Acc_LotNumberLow - device low lot number value
— Acc_PartNumber - device part number
— Acc_XPositiveTestDeflection - device self test positive deflection values for X axis
— Acc_YPositiveTestDeflection - self test positive deflection values for Y axis
— Acc_XFullScaleAccelerationRange - X self test magnitude selection
— Acc_YFullScaleAccelerationRange - Y self test magnitude selection
— Acc_DeviceReset - this device reset flag is set during device initialization following a device reset
— Acc_X_OffsetOverRange - the offset monitor over range flag is set if the acceleration signal of the X axis reaches
the specified offset limit
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Acc_Y_OffsetOverRange - the offset monitor over range flag is set if the acceleration signal of the Y axis reaches
the specified offset limit
Acc_SpiMisoError - the MISO data mismatch flag is set when a MISO Data mismatch fault occurs
Acc_DeviceInitFlag - the device initialization flag is set during the interval between negation of internal reset and
completion of internal device initialization
Acc_SigmaDeltaOverRange - the sigma delta modulator over range flag is set if the sigma delta modulator for
either axis becomes saturated
Acc_InterDataError - the internal data error flag is set if a customer or OTP register data CRC fault or other internal
fault is detected
Acc_FuseWarning - the fuse warn bit is set if a marginally programmed fuse is detected
Acc_InitEnd - the ENDINIT bit is a control bit use to indicate that the user has completed all device and system
level initialization tests, and that Mesquite will operate in normal mode
Acc_SignData - this parameter determines the format of acceleration data results
Acc_OffsetMoni - offset monitor circuit is enable/disable
Acc_ArmOutput - the ARM Configuration type select the mode of operation for the ARM_X/PCM_X,
ARM_Y/PCM_Y pins
Acc_XAxisSelfTest - enable or disable the self-test circuitry for X axis
Acc_YAxisSelfTest - enable or disable the self-test circuitry for Y axis
Acc_XLowPassFilter - the low pass filter selection bits independently select a low-pass filter for X axis
Acc_YLowPassFilter - the low pass filter selection bits independently select a low-pass filter for Y axis
Acc_XArmPulseStretch - pulse stretch time for X arming outputs
Acc_YArmPulseStretch - pulse stretch time for Y arming outputs
Acc_XArm_PosWin_CountLimit - X axis positive arming window size definitions or arming count limit definitions
function (depending on the state of the Acc_ArmOutput variable)
Acc_YArm_PosWin_CountLimit - Y axis positive arming window size definitions or arming count limit definitions
function (depending on the state of the Acc_ArmOutput variable)
Acc_Arm_XNegWinSize - X axis negative arming window size definitions (meaning depend on the state of the
Acc_ArmOutput variable)
Acc_Arm_YNegWinSize - Y axis negative arming window size definitions (meaning depend on the state of the
Acc_ArmOutput variable)
Acc_XArmPositiveThreshold - this value contain the X axis positive threshold to be used by the arming function
Acc_YArmPositiveThreshold - this value contain the Y axis positive threshold to be used by the arming function
Acc_XArmNegativeThreshold - this value contain the X axis negative thresholds to be used by the arming
function
Acc_YArmNegativeThreshold - this value contain the Y axis negative thresholds to be used by the arming
function
Acc_CountValue - value in the register increases by one count every 128 μs and the counter rolls over every
32.768 ms
Acc_XOffsetCorrection - the most recent X axis offset correction increment/decrement value from the offset
cancellation circuit
Acc_YOffsetCorrection - the most recent Y axis offset correction increment/decrement value from the offset
cancellation circuit
Parameters of the Acc_GetAccelData API function:
•
Spi_Channel (Acc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
AccelCmdX (Acc_XAccelerationDataType) - X axis acceleration data request
•
AccelCmdY (Acc_YAccelerationDataType) - Y axis acceleration data request
•
Status (Acc_AccelStatusType) output data structure containing the accelerometer X/Y moving values and device
status:
— AccelDataX - X axis acceleration data
— AccelDataY - Y axis acceleration data
— AccelRespTypeX - type of the X axis acceleration response
— AccelRespTypeY - type of the Y axis acceleration response
— Acc_DeviceReset - device reset flag is set during device initialization following a device reset
— Acc_X_OffsetOverRange - the offset monitor over range flag is set if the acceleration signal of the X axis reaches
the specified offset limit
— Acc_Y_OffsetOverRange - the offset monitor over range flag is set if the acceleration signal of the Y axis reaches
the specified offset limit
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Acc_SpiMisoError - the MISO data mismatch flag is set when a MISO Data mismatch fault occurs
Acc_DeviceInitFlag - the device initialization flag is set during the interval between negation of internal reset and
completion of internal device initialization
Acc_SigmaDeltaOverRange - the sigma delta modulator over range flag is set if the sigma delta modulator for
either axis becomes saturated
Acc_InterDataError - the internal data error flag is set if a customer or OTP register data CRC fault or other internal
fault is detected
Acc_FuseWarning - the fuse warn bit is set if a marginally programmed fuse is detected
Acc_CountValue - value in the register increases by one count every 128 μs and the counter rolls over every
32.768 ms
Parameters of the Acc_ProgramCmd API function:
•
Spi_Channel (Acc_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
RegAddress (uint16) - address of the selected IC register
•
Data (uint16) - data
•
SpiResponse (uint16) - response to the sent command
A.5
SQUIB Driver
The SQUIB driver is created as a separate software module. The main advantage is full HW abstraction and API independence
in used MCU family. The driver API covers the entire functionality of the squib driver, which means all firing commands and
devices statuses can be controlled by API functions.
The SQUIB Driver is dependent on the COM layer (basic SPI communication) and on the GPIO driver (General Purpose
Input/Output), which provides basic functions for reading status on the arming pins.
Figure 7-7. SQUIB SW Driver Concept
Table 7-3. SQUIB SW Driver API
Function Name
Function Parameters
Return Type
Function Description
Squib_Init
Spi_Channel [in]
Squib_ReturnType
Initialize the SQUIB device and returns the
confirmation of the initialization.
Squib_Fire
Spi_Channel [in]
Squib_Fire [in]
Squib_ReturnType
This function provide explosion of the selected
SQUIB driver
Squib_GetStatus
Spi_Channel [in]
*Status [out]
Squib_ReturnType
Return the status of the SQUIB drivers (1A, 1B,
2A and 2B) and common status of the SQUIB IC.
Squib_ProgramCmd
Spi_Channel [in]
Command [in]
Data [in]
Delay [in]
SpiResponse [out]
Squib_ReturnType
Send any SQUIB command to the IC device and
read its response.
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A.6
SQUIB Parameters Detail Descriptions
Brief description of input and output API parameters is in the following paragraphs. Descriptions contains only a verbal description
of the parameter. Values which each variable acquires is described in the header file SQUIB.h.
Parameters of the Squib_Init API function:
•
Spi_Channel (Squib_SpiChannelType) - logical SPI channel number (not physical SPI channel)
Parameters of the Squib_GetStatus API function:
•
Spi_Channel (Squib_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Status (Squib_StatusType) output status structure containing the complete status of the ACC
— Squib_Stat1ACurrTime - firing current in 1A squib line and records the “ON” time in which the IMEAS current is
above the threshold for 1A squib
— Squib_Stat1BCurrTime - firing current in 1B squib line and records the “ON” time in which the IMEAS current is
above the threshold for 1B squib
— Squib_Stat2ACurrTime - firing current in 2A squib line and records the “ON” time in which the IMEAS current is
above the threshold for 2A squib
— Squib_Stat2BCurrTime - firing current in 2B squib line and records the “ON” time in which the IMEAS current is
above the threshold for 2B squib
— Squib_Stat1ACurrent - line 1A FET driver current limit measurement status
— Squib_Stat1BCurrent - line 1B FET driver current limit measurement status
— Squib_Stat2ACurrent - line 2A FET driver current limit measurement status
— Squib_Stat2BCurrent - line 2B FET driver current limit measurement status
— Squib_Stat1ALowSideThermalShut - 1A Low Side Squib driver thermal shutdown status
— Squib_Stat1AHighSideThermalShut - 1A High Side Squib driver thermal shutdown status
— Squib_Stat1BLowSideThermalShut - 1B Low Side Squib driver thermal shutdown status
— Squib_Stat1BHighSideThermalShut - 1B High Side Squib driver thermal shutdown status
— Squib_Stat2ALowSideThermalShut - 2A Low Side Squib driver thermal shutdown status
— Squib_Stat2AHighSideThermalShut - 2A High Side Squib driver thermal shutdown status
— Squib_Stat2BLowSideThermalShut - 2B Low Side Squib driver thermal shutdown status
— Squib_Stat2BHighSideThermalShut - 2B High Side Squib driver thermal shutdown status
— Squib_Stat1VdiagResult - firing supply voltage (VDIAG_1) diagnostics - voltage level on the VDIAG_1 pin
— Squib_Stat1HSSafingSens - High Side Safing sensor diagnostics - monitors the VFIRE_XX pin connection to the
VDIAG_1 pin
— Squib_Stat2VdiagResult - firing supply voltage (VDIAG_2) diagnostics - voltage level on the VDIAG_2 pin
— Squib_Stat2HSSafingSens - High Side Safing sensor diagnostics - monitors the VFIRE_XX pin connection to the
VDIAG_2 pin
— Squib_1AShBatt - Squib short-to-battery diagnostics - voltage level on the SENSE_1A pin
— Squib_1AShGnd - Squib short-to-ground diagnostics - voltage level on the SENSE_1A pin
— Squib_1BShBatt - Squib short-to-battery diagnostics - voltage level on the SENSE_1B pin
— Squib_1BShGnd - Squib short-to-ground diagnostics - voltage level on the SENSE_1B pin
— Squib_2AShBatt - Squib short-to-battery diagnostics - voltage level on the SENSE_2A pin
— Squib_2AShGnd - Squib short-to-ground diagnostics - voltage level on the SENSE_2A pin
— Squib_2BShBatt - Squib short-to-battery diagnostics - voltage level on the SENSE_2B pin
— Squib_2BShGnd - Squib short-to-ground diagnostics - voltage level on the SENSE_2B pin
— Squib_Stat1ALowSideCont - continuity status for the Low Side driver SQB_LO_1A connection
— Squib_Stat1BLowSideCont - continuity status for the Low Side driver SQB_LO_1B connection
— Squib_Stat2ALowSideCont - continuity status for the Low Side driver SQB_LO_2A connection
— Squib_Stat2BLowSideCont - continuity status for the Low Side driver SQB_LO_2B connection
— Squib_1AOpnShBatt - Squib 1A harness short-to-battery status with an open Squib
— Squib_1AOpnShGnd - Squib 1A harness short-to-ground status with an open Squib
— Squib_1BOpnShBatt - Squib 1B harness short-to-battery status with an open Squib
— Squib_1BOpnShGnd - Squib 1B harness short-to-ground status with an open Squib
— Squib_2AOpnShBatt - Squib 2A harness short-to-battery status with an open Squib
— Squib_2AOpnShGnd - Squib 2A harness short-to-ground status with an open Squib
— Squib_2BOpnShBatt - Squib 2B harness short-to-battery status with an open Squib
— Squib_2BOpnShGnd - Squib 2B harness short-to-ground status with an open Squib
— Squib_StatVfireBTested - reports VFIRE testing has been finished
Airbag Reference Demonstrator, Rev. 3.0
Freescale Semiconductor
35
SW Concept
—
—
—
—
—
—
—
—
—
—
—
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—
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—
—
—
—
Squib_StatVfire - reports of the voltage level on the VFIRE_XX pin
Squib_StatV1diagV1 - firing supply voltage status - VDIAG_V1 voltage on the VDIAG1 pin
Squib_StatV1diagV2 - firing supply voltage status - VDIAG_V2 voltage on the VDIAG1 pin
Squib_StatV1diagV3 - firing supply voltage status - VDIAG_V3 voltage on the VDIAG1 pin
Squib_StatV1diagV4 - firing supply voltage status - VDIAG_V4 voltage on the VDIAG1 pin
Squib_StatV2diagV1 - firing supply voltage status - VDIAG_V1 voltage on the VDIAG2 pin
Squib_StatV2diagV2 - firing supply voltage status - VDIAG_V2 voltage on the VDIAG2 pin
Squib_StatV2diagV3 - firing supply voltage status - VDIAG_V3 voltage on the VDIAG2 pin
Squib_StatV2diagV4 - firing supply voltage status - VDIAG_V4 voltage on the VDIAG2 pin
Squib_StatFen1 - status of the FEN_1 arming input pin
Squib_StatFen2 - status of the FEN_2 arming input pin
Squib_StatFen1Latch - FEN1 latch status
Squib_StatFen2Latch - FEN2 latch status
Squib_StatRdiag - reports status of the R_DIAG resistor
Squib_StatRlimit1 - reports the R_LIMIT_1 resistor value - reference currents derived by the R_LIMIT_1 and
R_LIMIT_2 resistors
Squib_StatRlimit2 - reports the R_LIMIT_2 resistor value - reference currents derived by the R_LIMIT_1 and
R_LIMIT_2 resistors
Squib_DeviceType - identifier the squib IC as a four- or two-channel squib driver IC
Squib_StatVfireRtn1 - reports the resistance on the VFIRE_RTN1 pin for open pin connections
Squib_StatVfireRtn2 - reports the resistance on the VFIRE_RTN2 pin for open pin connections
Squib_Stat1AResistance - Squib 1A resistance value
Squib_Stat1BResistance - Squib 1B resistance value
Squib_Stat2AResistance - Squib 2A resistance value
Squib_Stat2BResistance - Squib 2B resistance value
Squib_Stat1ALoopsShorts - reports shorts between 1A squib lines and other firing loops
Squib_Stat1BLoopsShorts - reports shorts between 1B squib lines and other firing loops
Squib_Stat2ALoopsShorts - reports shorts between 2A squib lines and other firing loops
Squib_Stat2BLoopsShorts - reports shorts between 2B squib lines and other firing loops
Squib_Stat1ALoopsShortsAddIC - reports shorts between squib 1A loop and other loops on additional ICs
Squib_Stat1BLoopsShortsAddIC - reports shorts between squib 1B loop and other loops on additional ICs
Squib_Stat2ALoopsShortsAddIC - reports shorts between squib 2A loop and other loops on additional ICs
Squib_Stat2BLoopsShortsAddIC - reports shorts between squib 2Bloop and other loops on additional ICs
Parameters of the Squib_Fire API function:
•
Spi_Channel (Squib_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Squib_Fire (Squib_FireType) - firing commands for squibs pairs or for separate Low/High side
Parameters of the Squib_ProgramCmd API function:
•
Spi_Channel (Squib_SpiChannelType) - logical SPI channel number (not physical SPI channel)
•
Command (Squib_ProgCmdType) - Squib command
•
Data (uint8) - data
•
Delay (uint8) - Squib diagnostic delay time
•
SpiResponse (uint8) - response to the sent command
Airbag Reference Demonstrator, Rev. 3.0
36
Freescale Semiconductor
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Airbag Reference Demonstrator Implementation details
Airbag Reference Demonstrator Implementation
details
Airbag Reference Demonstrator Schematics
Figure 7-8. Block Schematic of the ARD Board
Airbag Reference Demonstrator, Rev. 3.0
37
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Airbag Reference Demonstrator Implementation details
Figure 7-9. ARD Board - MCU + Central Accelerometer
Airbag Reference Demonstrator, Rev. 3.0
Freescale Semiconductor
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Airbag Reference Demonstrator Implementation details
Figure 7-10. Airbag System Basis Chip
Airbag Reference Demonstrator, Rev. 3.0
39
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Figure 7-11. Squibs
Airbag Reference Demonstrator, Rev. 3.0
Freescale Semiconductor
Freescale Semiconductor
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Airbag Reference Demonstrator Implementation details
Figure 7-12. Main Automotive Connector
Airbag Reference Demonstrator, Rev. 3.0
41
Airbag Reference Demonstrator Implementation details
B.2
ARD Placement and Layout
Figure 7-13. Top View and Placement
Airbag Reference Demonstrator, Rev. 3.0
42
Freescale Semiconductor
Airbag Reference Demonstrator Implementation details
Figure 7-14. Bottom View
B.3
Bill of Materials
Table 7-4. Bill of Materials
Item
Number
Quantity
Part Reference
Value
Description
1
34
C11,C12,C14,C16,C21,C22,C46,C61,C64,
C72,C73,C74,C98,C99,C100,C101,C102,
C103,C104,C105,C106,C107,C108,C109,
C110,C111,C112,C113,C114,C115,C116,
C117,C118
2
3
C13,C15,C17
0.22 μF
CAP CER 0.22UF 16V 10% X7R 0603
3
4
C18,C19,C45,C51
1.0 μF
CAP CER 1.0UF 25V 10% X5R 0603
4
9
C31,C81,C82,C83,C84,C85,C86,C87,C88
5
1
C32
0.1 μF
0.047 μF
1.0 μF
CAP CER 0.10UF 25V 10% X7R 0603
CAP CER 0.047UF 50V 10% X7R 0603
CAP ALEL 1.0UF 50V 20% - SMT
6
1
C33
100 μF
CAP ALEL 100UF 25V 20% - SMT
7
1
C34
220 μF
CAP ALEL 100UF 50V 20% - RADIAL TH
8
1
C35
0.22 μF
CAP CER 0.22UF 50V 5% X7R 1206
9
4
C36,C37,C38,C39
2200 μF
10
5
C40,C62,C63,C65,C66
0.1 μF
CAP CER 0.1UF 50V 5% X7R 0805
11
1
C41
330 pF
CAP CER 330PF 50V 5% C0G 0603
11
C42,C49,C89,C90,C91,C92,C93,C94,C95,
C96,C97
10 nF
CAP CER 0.01UF 50V 5% X7R 00603
12
CAP ALEL 2200UF 35V +30/0% - RADIAL
13
1
C43
47 μF
CAP TANT 47UF 16V 10% - 6032-28
14
1
C44
-0.12 μF
CAP CER 0.12UF 50V 10% X7R 0603
Airbag Reference Demonstrator, Rev. 3.0
Freescale Semiconductor
43
Airbag Reference Demonstrator Implementation details
Table 7-4. Bill of Materials
Item
Number
Quantity
15
1
C47
4.7 μF
CAP TANT 4.7UF 10V 10% - 3216-18
16
1
C50
47 μF
CAP TANT 47UF 25V 10% - 7343
17
3
C52,C75,C77
220 pF
CAP CER 220PF 50V 10% X7R 0603
18
1
C71
2.2 μF
CAP CER 2.2UF 25V 10% X7R 0805
19
1
C76
2200 pF
CAP CER 2200PF 50V 5% X7R 0603
20
1
D11
RED
LED RED SGL 2MA 0805 SMT
21
1
D12
YELLOW
LED YEL SGL 2MA 0805 SMT
22
1
D31
ES1D-13-F
23
2
D32,D33
Part Reference
Value
SS26T3
Description
DIODE RECT 1A 200V SMA SMT
DIODE SCH PWR 2A 60V SMB
24
1
D34
ES2B
25
1
J11
HDR 2X3
26
1
J81
CON_2X28
27
1
JP11
HDR_1X6
28
1
L31
22UH
IND PWR [email protected] 2.25A 20% SMT
29
1
L32
150UH
IND PWR [email protected] 1.35A 20% SMT
30
1
L33
220UH
31
1
Q31
BCP69T1
32
1
R11
3.3K
RES MF 3.30K 1/10W 1% 0603
33
20
R12,R13,R14,R15,R16,R17,R18,R35,R36,
R37,R38,R39,R40,R41,R61,R62,R63,R64,
R65,R66
10K
RES TF 10K 1/10W 5% RC0603
34
2
R19,R20
1.6K
RES MF 1.6K 1/10W 1% 0603
35
1
R21
1.0M
RES MF 1.0M 1/10W 1% 0603
36
1
R31
1.0K
RES MF 100K 1/4W 1% 1206
37
2
R32,R34
38
1
R33
100K
215 OHM
DIODE RECT ULTRA FAST 2A 100V DO-214AA
HDR 2X3 TH 2.54MM CTR 340H AU
CON 2X28 ASM RA TH 3MM SP 30.7MM - 118L
HDR 1X6 TH 100MIL SP 408H AU
IND PWR [email protected] 1.15A 20% SMT
TRAN PNP AUD 1A 20V SOT223
RES TF 100K 1/10W 1% 0603
RES MF 215 OHM 1/2W 1% 2010
39
1
R42
0
RES MF ZERO OHM 1/10W 0603
40
2
R71,R72
60.4
RES MF 60.4 OHM 1/8W 1% 0805
41
4
R81,R82,R83,R84
3.3
RES MF 3.30 OHM 1/8W 1% 0805
42
1
U11
IC MCU 16BIT 128K FLASH 12K RAM 50MHZ
MCc9S12XEG128
5.5V QFP80
43
1
U12
44
2
U13,U14
45
1
U31
46
2
47
1
U71
CAN Phy
48
1
X11
4MHZ
U61,U62
MMA6801QR2
NL27WZ32
MC33789
MC33789EK
IC GATE OR DUAL 2-INPUT 1.65-5.5V US8
IC CTRL AIRBAG 5.2-20V LQFP64EP
IC SQUIB DRV AIRBAG FOUR CHANNEL 5V
SOICW32
IC HS CAN XCVR 5V SOIC14
XTAL 4MHZ RSN 6V SMT
Freescale does not assume liability, endorse, or warrant components from external manufacturers that are referenced in circuit drawings or
tables. While Freescale offers component recommendations in this configuration, it is the customer’s responsibility to validate their application.
Airbag Reference Demonstrator, Rev. 3.0
44
Freescale Semiconductor
Acronyms
Appendix C
Acronyms
ACC
Central Accelerometer
ADC
Analog To Digital Converter
API
Application Protocol Interface
ARD
Airbag Reference Demonstrator
ASBC
Airbag System Basis Chip
BAM
Boot Assist Module
BOS
Basic Operation System
CAN
Controller Area Network
COM
Serial Communication Port
ECU
Electronic Control Unit
EEPROM
Electrically Erasable Programmable Read-Only Memory
GUI
Graphical User Interface
GPT
General Purpose Timer
GPO
General Purpose Output
LIN
Local Interconnect Network
MUX
Multiplexer
N/A
Not Applicable
PCB
Printed Circuit Board
PSI5
Peripheral Sensor Interface 5
SPI
Serial Peripheral Interface
SW
Software
SQUIB
Automobile AirBag
VREG
Voltage Regulator
WD
Watchdog
Airbag Reference Demonstrator, Rev. 3.0
Freescale Semiconductor
45
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Document Number: ARDRM
Rev 3.0
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