PSI5 Technical Specification 121008_psi5_spec_v2d1_base.doc V2.1 08.10.2012
PSI5
All rights including industrial property rights and all rights of disposal such as copying and passing to third parties reserved.
Peripheral Sensor Interface
Technical
Specification
Page I
V2.1
Peripheral Sensor Interface
for Automotive Applications
PSI5 Technical Specification 121008_psi5_spec_v2d1_base.doc V2.1 08.10.2012
PSI5
All rights including industrial property rights and all rights of disposal such as copying and passing to third parties reserved.
Peripheral Sensor Interface
Technical
Specification
Page II
V2.1
Contents
1 Introduction 1
1.1 Description ....................................................................................................................................... 1
1.2 PSI5 Main Features ......................................................................................................................... 1
1.3 Scope ............................................................................................................................................... 2
1.4 Legal Information ............................................................................................................................. 2
2 System Setup & Operation Modes 4
2.1 System Setup ................................................................................................................................... 4
2.2 PSI5 Operation Modes ..................................................................................................................... 5
2.3 Asynchronous Operation (PSI5-A) ................................................................................................... 6
2.3.1 Asynchronous Single Sensor Configuration .......................................................................... 6
2.4 Synchronous Operation ................................................................................................................... 7
2.4.1 Timing of Synchronous Operation Modes ............................................................................. 7
2.4.2 Bus Operation Principle ......................................................................................................... 8
2.5 Preferred Daisy-Chain Mode: Parallel Initialization Phase .............................................................. 9
2.5.1 Synchronous Parallel Bus Mode (PSI5-P) ........................................................................... 11
2.5.2 Synchronous Universal Bus Mode (PSI5-U) ....................................................................... 12
2.5.3 Synchronous Daisy Chain Bus Mode (PSI5-D) ................................................................... 13
2.5.4 Sensor Cluster / Multichannel .............................................................................................. 14
3 Sensor to ECU communication 15
3.1 Physical Layer ................................................................................................................................ 15
3.1.1 Bit Encoding - Sensor to ECU Communication ................................................................... 15
3.2 Data Link Layer .............................................................................................................................. 16
3.2.1 Data Frames - Sensor to ECU Communication ................................................................... 16
3.2.2 Error Detection ..................................................................................................................... 17
3.2.3 Frame Format ...................................................................................................................... 18
3.3 Data Range .................................................................................................................................... 19
3.3.1 Data Range (10 Bit) ............................................................................................................. 19
3.3.2 Scaling of Data Range (for data words longer than 10 bit) ................................................. 20
3.4 Serial Channel ................................................................................................................................ 21
4 ECU to Sensor Communication 23
4.1 Physical Layer ................................................................................................................................ 23
4.1.1 „Tooth Gap“ method ............................................................................................................. 23
4.1.2 „Pulse Width“ method .......................................................................................................... 23
4.2 Data Link Layer .............................................................................................................................. 24
5 Application Layer Implementations 28
5.1 Sensor Initialization / Identification ................................................................................................. 28
5.1.1 Frame Format - Data range initialization ............................................................................. 28
5.1.2 Meta Information .................................................................................................................. 30
5.1.3 Vendor ID ............................................................................................................................. 30
5.2 Bidirectional Communication.......................................................................................................... 31
5.2.1 Sensor Adresses .................................................................................................................. 31
5.2.2 Function Codes and responses for bidirectional communication – Frame 1 to 3 ............... 32
5.2.3 Returned Error Codes – Sensor Response for Frame 1-3 .................................................. 33
6 Parameter Specification 34
6.1 General Parameters ....................................................................................................................... 34
6.1.1 Absolute Maximum Ratings ................................................................................................. 34
6.1.2 System Parameters ............................................................................................................. 34
6.2 Sensor Power-on Characteristics .................................................................................................. 38
6.3 Undervoltage Reset and Microcut Rejection ................................................................................. 39
PSI5 Technical Specification 121008_psi5_spec_v2d1_base.doc V2.1 08.10.2012
PSI5
All rights including industrial property rights and all rights of disposal such as copying and passing to third parties reserved.
Peripheral Sensor Interface
Technical
Specification
Page III
V2.1
6.4
Data Transmission Parameters ..................................................................................................... 40
6.5 Synchronization Signal ................................................................................................................... 41
6.6 Timing Definitions for synchronous operation modes .................................................................... 44
6.6.1 Generic Time slot calculation ............................................................................................... 44
7 System Configuration & Test Conditions 47
7.1 System Modelling ........................................................................................................................... 47
7.1.1 Supply Line Model ............................................................................................................... 47
7.2 Asynchronous Mode ...................................................................................................................... 47
7.3 Parallel Bus Mode .......................................................................................................................... 48
7.4 Universal Bus Mode ....................................................................................................................... 49
7.5 Daisy Chain Bus Mode ................................................................................................................... 49
7.6 Test Conditions & Reference Networks – Sensor Testing ............................................................ 50
7.6.1 Reference Networks for Asynchronous Mode and Parallel Bus Mode ............................... 50
7.6.2 Reference Networks for Universal Bus Mode and Daisy Chain Bus Mode ......................... 52
7.6.3 Test Parameter Specification ............................................................................................... 53
7.6.4 Sensor Reference Tests ...................................................................................................... 53
7.7 Test Conditions & Reference Networks - Transceiver / ECU Testing ........................................... 54
7.7.1 Reference Networks for Asynchronous Mode and Parallel Bus Mode ............................... 54
7.7.2 ECU Reference Tests .......................................................................................................... 54
8 Interoperability Requirements 56
9 Document History & Modifications 57
PSI5 Technical Specification 121008_psi5_spec_v2d1_base.doc V2.1 08.10.2012
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Peripheral Sensor Interface
Technical
Specification
Page 1 / 59
V2.1
1 Introduction
1.1 Description
The Peripheral Sensor Interface (PSI5) is an interface for automotive sensor applications. PSI5 is an open 1
standard based on existing sensor interfaces for peripheral airbag sensors, already proven in millions of 2
airbag systems. The technical characteristics, the low implementation overhead as well as the attractive 3
cost make the PSI5 also suitable for many other automotive sensor applications. 4
Development goal of the PSI5 is a flexible, reliable communication standard for automotive sensor 5
applications that can be used and implemented free of charge. 6
The PSI5 development and the publication of this technical specification are responsibly managed by the 7
“PSI5 Steering Committee”, formed by the companies Autoliv, Bosch, and Continental. 8
This PSI5 technical specification V2.1 is a joint development of the companies Autoliv, Bosch, Continental, 9
Analog Devices, CS Group, ELMOS, Freescale, Hella, IHR, Infineon, Seskion, ST, TRW and OnSemi. 10
1.2 PSI5 Main Features
Main features of the PSI5 are high speed and high reliability data transfer at lowest possible 11
implementation overhead and cost. PSI5 covers the requirements of the low-end segment of digital 12
automotive interfaces and offers a universal and flexible solution for multiple sensor applications. It is 13
characterized by 14
Two-wire current interface 15
Manchester coded digital data transmission 16
High data transmission speed of 125kbps or optional 189kbps 17
High EMC robustness and low emission 18
Wide range of sensor supply current 19
Variable data word length (10 to 28 bit with one bit granularity) 20
Asynchronous or synchronous operation and different bus modes 21
Bidirectional communication 22
This updated Version 2.1 contains several new features in terms of Physical and Data Link Layer 23
parameters in order to enlarge the application range of the PSI5 Interface. Due to backward compatibility 24
established parameters according to Specification V1.3 are still valid; the alternative implementations are 25
mainly optional and specifically indicated. 26
Though, general interface parameters are given within this Basic Specification document, application 27
specific frameworks and conditions are given in the effective substandards “airbag”, “vehicle dynamics 28
control” and “powertrain”. Recommended operation modes and system configurations are given therein 29
along with configurations that are forbidden. 30
PSI5 Technical Specification 121008_psi5_spec_v2d1_base.doc V2.1 08.10.2012
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Peripheral Sensor Interface
Technical
Specification
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V2.1
Please be aware, that not every feature can be combined among one other. Hence it is in responsibility of 31
the system vendor to evaluate what features are necessary to fulfill the system requirements and assure 32
that the combination of features is compatible. 33
1.3 Scope
This document describes the interface according to the ISO/OSI reference model and contains the 34
corresponding parameter specifications. PSI5 standardizes the low level communication between 35
peripheral sensors and electronic control units. 36
1.4 Legal Information
The specification may be reproduced or copied, subject to acceptance of the contents of this document. 37
No part of this specification may be modified or translated in any form or by any means without prior written 38
permission of Autoliv, Bosch, and Continental. With their permission Autoliv, Bosch, and Continental 39
assume no liability for the modifications or translations made by third parties. 40
In case Autoliv, Bosch, and Continental permit any of the aforementioned modifications or translations 41
Autoliv, Bosch, and Continental shall be entitled to use such modifications or translations free of charge for 42
future versions of the PSI5 protocol and make such future versions available to third parties under the 43
same terms and conditions as for the PSI5 protocol. 44
Disclaimer 45
The specification and all enclosed documents are provided to you "AS IS". You assume total responsibility 46
and risk for your use of them including the risk of any defects or inaccuracies therein. 47
Autoliv, Bosch, Continental and the other members of the PSI5 Consortium do not make, and expressly 48
disclaim, any express or implied warranties of any kind whatsoever, including, without limitation, implied 49
warranties of merchantability of fitness for a particular purpose, warranties or title or non-infringement.
50
The PSI5-consortium shall not be liable for 51
(a) any incidental, consequential, or indirect damages (including, without limitation, damages for loss 52
of profits, business interruption, loss of programs or information, and the like) arising out of the use 53
of or inability to use the specification or enclosed documents, 54
(b) any claims attributed to errors, omissions, or other inaccuracies in the specification or enclosed 55
documents. 56
As far as personal injuries are caused due to the specification or any of the enclosed documents and to the 57
extent the mandatory laws of the law applicable restrict the limitation of liability in such cases or in other 58
circumstances as for example liability due to wilful intent, fraudulently concealed defects or breach of 59
cardinal obligations, the mandatory law applicable shall remain unimpaired. 60
