can lin flexray automotive seminar

Automotive Low Speed Serial Bus Analysis

with Tektronix Oscilloscopes

2

Automotive Serial Bus Overview

I2C

SPI

CAN

FlexRay

USB (Infotainment: UserDevice Access)

MOST 50 / 150 (Infotainment: Network)

Ethernet (BroadR-Reach PHY , Broadcom)

MIPI (D-Phy, DSI / CSI)

HDMI / MHL

SPI

3

Trace Data Flow Through an Automotive Network

Trace serial data flow between nodes through a network Simultaneously display messages at transmitter and receiver to verify continuity and

propagation delays

Trace serial data flow between network segments separated by a gateway Simultaneously display messages from multiple buses, at different speeds, or even

different bus standards

Gateway

Mobile Phone

Car

Radio

Multi Media

Module

CAN

Air Bag ABS

ABS

CAN

Climate

Control

Left DoorRight Door

Seat

Control

CAN

Sensor

Motor

LIN

Engine

ControlESP

Gear

Box

CAN

Diagnostic LIN

Data Backbone for ADAS (Active Driver Assistance Systems)

Data Interchange with other specific automotive bus systems (CAN/Flexray)

Automotive Bus Technology - Application Areas

Source: www.mostcooperation.com

4

Tektronix Confidential

Midrange Scope Portfolio

MSO/DPO2000

MSO/DPO3000

MSO/DPO4000B

MSO/DPO5000

DPO7000C

200 - 100 MHz

1 GS/s

500 - 100 MHz

2.5 GS/s

1 GHz 350 MHz

5 2.5 GS/s

2 GHz 350 MHz

10 - 5 GS/s

3.5 GHz 500 MHz

40 - 5 GS/s

1M Samples Max 5 M Samples Max 20 M Samples Max 250 M Samples Max 500 M Samples Max

MS WIN 7 Embd. OS

Debugging Serial Buses with the MSO/DPO Series

4000B Series 3000 Series 2000 Series

Bandwidth 1 GHz, 500 MHz, 350 MHz 500 MHz, 300 MHz, 100 MHz 200 MHz, 100 MHz

Channels 4 analog

16 digital (MSO Series)

2 or 4 analog


2 or 4 analog


Record Length 20 M points 5 M points 1 M points

Serial Bus

Analysis

I2C, SPI

USB

Ethernet

CAN, LIN, FlexRay

RS-232/422/485/UART

I2S/LJ/RJ/TDM

MIL-STD-1553

I2C, SPI

CAN, LIN

RS-232/422/485/UART

I2S/LJ/RJ/TDM

I2C, SPI

CAN, LIN

RS-232/422/485/UART

# of

Simultaneous

Decoded Buses

4 2 2

Automated Trigger, Decode and Search for Serial Buses

7

Speed debug of serial buses with the MSO/DPO5000 Series

Automated Decode, Trigger, Search and Eye Diagram Analysis

MSO/DPO5000 Series 350 MHz to 2 GHz

Up to 250 M record length

Comprehensive verification including compliance with jitter

and eye validation

Physical layer testing for USB 2.0 and Ethernet 10/100/1000BASE-T

Serial bus decode, trigger and search support for:

I2C

SPI

UART/RS-232

USB 2.0

MOST 50 / 150

In-Depth Analysis of Serial Buses with the DPO7000 Series

DPO7000 Series 500 MHz to 3.5 GHz

Up to 500 M record length

Physical layer testing for USB 2.0, Ethernet and MIPI

Serial data characterization with jitter and eye analysis

Supported serial buses:

I2C

SPI

CAN

LIN

FlexRay

UART/RS-232

MOST 50 / 150

Automated Decode, Trigger, Search and Eye Diagram Analysis

V6.4.0 Firmware for 5k, 7kC, 70kC/D WIN7 Scopes

Great new features New bus standards support Improvements to Visual Trigger New mark all trigger events Search capability Improved Zoom and Cursor button operation Measurements on digital channels MATLAB and MS Visual Studio math plug-in functionality

Performance improvements Faster MSO/DPO5k operation FastFrame and long record length speed increased

Defect fixes for many customer-reported bugs

Larger HDD and SSD

New PS2 power bundle

Available end of June 2012 Available for all demo units now - update yours today! New one-step complete update with deployment package

New Standards Support

CAN/LIN/FlexRay (trigger/decode/search)

MIL-STD-1553B (trigger/decode/search)

PCI Express gen 1/2/3 (trigger (70k)/decode/search)

SPI 2-wire (trigger/decode/search)

8b/10b added to MSO/DPO5k and DPO7kC (decode/search)

MIPI D-PHY added to MSO/DPO5k (decode/search)

Electrical Compliance Measurements MOST 50 and 150 electrical compliance

Thunderbolt

LSS Trigger/Decode/Search

CAN/LIN/FlexRay: SR-AUTO

MIL-STD-1553: SR-AERO

2-Wire SPI added to SR-EMBD

CAN Bus: SR-AUTO

MIL-STD-1553: SR-AERO

2-Wire SPI: SR-EMBD

12

How do I probe serial digital buses?

Digital buses are not digital

Digital signals do not necessarily have only two discrete levels

Digital probes are not digital

Everything you know about analog probing still applies

Minimize DC and AC loading

Voltage measurements are always differential

Minimize lead inductance

The real signal must be delivered to the oscilloscopes hardware or software comparator, where it can be compared to the digital threshold value(s)

Bus and Waveforms display of I2C signal

13

What do the probing and acquisition architectures look like

3pF 100k

0.2pF

- +

front-panel connector

P6616 passive probe Digital input circuit (logic analyzer ASIC)

coax Acquisition

System

acquisition circuit

14

Digital Acquisition System

MSO/DPO4000B / 5000 Series and P6616 Digital Probe

high end digital specification

P6616 16-channel digital probe matched to

the digital acquisition system

Specification MSO4000 MSO4000B

Maximum Sample Rate 500MS/s

16.5GS/s with MagniVu

500MS/s

16.5GS/s with MagniVu

Maximum Input Toggle Rate 350 MHz 500 MHz

DC Input Voltage Range 15 V 42 Vpeak

Maximum Input Voltage

Swing

6 Vp-p

centered on threshold

30 Vp-p 200MHz 10 Vp-p >200 MHz

Input Impedance 20 kOhm 100 kOhm

Input Capacitance 3 pF 3 pF

Threshold Range -2 V to +5 V 40 V

Minimum Input Swing 500 mVp-p 400 mVp-p

Minimum Detectable Pulse 1.5 ns 1 ns

MSO5000

500MS/s 16.5GS/s with MagniVu

500 MHz

42 Vpeak

30 Vp-p 200MHz 10 Vp-p >200 MHz

100 kOhm

3 pF

40 V

400 mVp-p

1 ns

15

I2C (Inter-Integrated Circuit)

Used for chip-to-chip communication between microcontrollers and A/Ds, D/As, FPGAs, sensors, etc.

Uses two single-ended, bi-directional signals: clock and data (Half Duplex)

Any I2C device can be attached to the bus

Data rates: Standard Mode (100 kbps)

Fast Mode (400 kbps)

High Speed Mode (3.4 Mbps)

16

I2C (Physical Part)

Master Device

3

Device

4

SDA

SCL

+V

Pull-up resistors

17

Input Source Selection (example: I2C)

CH1 CH4

D0 D15 (MSO)

View different busses

simultaneously

Channel Labeling

18

I2C Message Structure

Start: Indicates the device is taking control of the bus and a message will follow

Address: 7-bit or 10-bit number representing the device address to read or write

Data: Integer number of bytes read from or written to the device

Acknowledge: 1-bit from the slave device acknowledging the masters actions

Stop: Indicating the message is complete and the master has released the bus

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1 0 1 0 0 0 0

Serial Debug

Manually Decoding Serial Bits

1 0 1 0 0 0 0

Engineers must manually count each bit and determine if it is a 1 or a 0

0 0 0 1 0 1 0 0 0 0 1 0 0 1 1 0 1

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Serial Debug

Manually Decoding Serial Bits

Engineers must then convert the data to an understandable format

First three bits are most significant digit of a 7-bit address

Read or Write

Most significant digit of 8-bit byte

4 1

Least significant digit of 8-bit byte

0 5 6 1

0 0 0 1 0 1 1 0 0 0 0 1 0 1 0 0 1 0 1 0 0 0 0 1

R

Next four bits are least significant digit of a 7-bit address

= Read data 14 and 16 from Address 50

21

There must be a better way

Serial Debug

Serial Triggering and Decode

I2C Decoding is done by oscilloscope for the engineer

22

I2C Message Flow Control

Acknowledge/No Acknowledge

Indicates success or failure of a data transmission or the continuation of a transfer

Generated by holding the SDA low on the 9th clock pulse

SDA

SCL . . . 1 2 3 8 9

SDA

SCL . . . 1 2 3 8 9

ACK

NACK

23 23

I2C Solution on Tektronix Oscilloscope

24

SPI (System Peripheral Interface)

Used primarily to communicate between microcontrollers and their immediate peripheral devices

Typical configuration has four signals: SCLK, MOSI, MISO, SS Data is simultaneously transmitted and received

SS line used to specify slave device

Each unique device on bus has its own SS signal from master

Multiple bus configurations are allowed Network can use 2-, 3-, or 4-wire bus topology

Data rates up to 50 Mbps

SS enables slave device to accept data

MOSI data from the master to a slave

MISO data from a slave to the master

SCLK serial clock driven by Master

SS

MOSI (n bits)

MISO (n bits)

SCLK

MSB LSB

MSB LSB

25

SPI (System Peripheral Interface)

SPI Bus Hardware Configurations

Single Master Multiple Slaves

Single Master hardwired to Single Slave

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Serial Debug

Serial Triggering and Decode

There is more than just decoding

Trigger on packet content

Search and mark packet content

View data in an Event Table format

View two buses simultaneously

I2C

CAN

SPI

LIN

RS-232

FlexRay

27

CAN (Controller Area Network)

Used for system-to-system communication in Automotive, Industrial Automation, and Medical Equipment

Serial asynchronous, multi-master, layered communication network Sophisticated error detection and error handling mechanisms

Flexible signaling support for low-cost implementation

Messages are broadcast to all nodes on the network

Physical bus is single-wire or dual-wire, and fault tolerant

Data rates from 5 kbps to 1 Mbps

CAN Physical Layer

Electronic

Control

Unit

CAN

Controller

Tx

Rx

Rx

Tx

CAN_H

CAN_L

CAN Bit Rate Min. CAN Pulse Width

1 Mbps 1 s

800 Kbps 1.25 s

500 Kbps 2 s

250 Kbps 4 s

125 Kbps 8 s

83.3 Kbps 12 s

62.5 Kbps 16 s

50 Kbps 20 s

33.3 Kbps 30 s

20 Kbps 50 s

10 Kbps 100 s

3.5V

2.5V

1.5V

recessive

dominant

recessive

CAN-H

CAN-L

1 0 1

CAN High Speed Differential Bus

Signal

CAN Bus Bit Rate Table

CAN is a differential BUS

Tx +

-

+

-

Rcv path +

-

+

-

CAN Physical Layer

Electronic

Control

Unit

CAN

Controller

Tx

Rx

Rx

Tx

CAN_H

CAN_L

3.5V

2.5V

1.5V

recessive

dominant

recessive

CAN-H

CAN-L

1 0 1

CAN High Speed Differential Bus

Signal

29

In-Depth Analysis of Network Performance

Locate and analyze signal integrity problems with eye diagrams

Characterize different oscillator tolerances and propagation delays between nodes for synchronizing the network

Monitor bus utilization to ensure efficient use of the network

120

120

Node 1 Node 2 Node 10

40 meters

Near End Far End

CAN

Network

Eye diagram measurements Fast Data Rates, More HF Loss

Reference Maxim Note HFDN-27.0 (Rev. 0, 09/03)

Tx +

-

+

-

Rcv path +

-

+

-

Clean, open, logical 1 & 0 at launch from transmitter

Smeared edges at end of long interconnect.

Logical 1 & 0 can be hard to distinguish at end of long interconnects; (this is often called a closed eye)

Fast, sharp, edges at transmitter launch

31

CAN Data and Remote Frame Overview

SOF: begins with a start of frame (SOF) bit Arbitration: Identifier (address) and Remote Transmission Request (RTR) bit

Control: 6 bits including Identifier Extension (IDE) bit and Data Length Code (DLC)

Data: zero to eight bytes of data CRC: 15-bit cyclic redundancy check code and a recessive delimiter bit ACK: acknowledge field is two bits long

EOF: 7 recessive bits indicate the end of frame (EOF) INT: intermission field of three recessive bits indicates the bus is free

32

Characterize System Timing

Characterize timing between bus messages and system operation Requires waveform displays time-correlated with decoded messages

Characterize timing differences which occur when adding a new network node to an existing network

Automotive application example: Measure worst-case time from crash sensor output to airbag activation

Measure variations in timing of airbag activation with varying levels of CAN bus traffic

33

CAN Bus DPO7000 CAN Trigger

34

CAN Bus DPO7000 CAN Analysis Application

Select Function :

Decoding Timing Analysis

35


Configure :

Trig.-Source Bus-Source

36


Trig.-Configure :

Field Type Field Value

37


Decoding Results :

Field Value Timing Result

38


Decoding Results :

Correlation to Acq.-Mem

39

Characterizing Oscillator Tolerance and Propagation Delay

Oscillator tolerance of a CAN node

Specify the specific ID for trigger condition

Result will include ACK and without ACK bit

With ACK bit, shows the impact of receiving CAN node

oscillator tolerance on

transmitting node

Propagation Delay Connect two channels to any

two CAN nodes

Result is directly available

40

Monitoring CAN Traffic for Bus Utilization

Measure at specific ID, error frame or

overload frame

Specifies percentage of time traffic present

in the CAN bus

Type of traffic can be analyzed

Frame count

Tektronix DPO7000 Series with TDSVNM option

41

CAN Trigger Overview

42

FlexRay 2.1 (3.0)

FlexRay is a automotive bus still being developed by a group of leading automotive companies and suppliers known as the FlexRay

Consortium

The physical bus can be unshielded twisted pair, or shielded twisted pair to improve EMC performance

FlexRay is a differential serial bus configured in three recurring segments: Header, Payload, and Trailer

Each frame contains a static and dynamic segment, and bus idle time concludes each frame

Transmitted data rates up to 10 Mbps

Automotive

Manufacturers are finding that existing automotive serial standards such as CAN and LIN do not have the speed, reliability, or redundancy required to address X-by-wire applications such as brake-by-wire or steer-by-wire.

43 43

FlexRay Frame Structure

Header Segment Contains Indicator Bits, Frame ID, Payload Length (in words), Header CRC, and Cycle Count

Payload Segment Contains data transferred by the frame. Maximum payload length is 127 words (254 bytes)

Trailer Segment Contains a single 24 bit field [three 8 bit CRC registers] for header and payload protection

44 44

FlexRay Terms and Abbreviations

TSS (Transmission Start Sequence): initiate network connection setup.

FSS (Frame Start Sequence): immediately follows TSS

Indicator Bits: provides Header Segment preamble information.

Frame Id (Frame Identifier): defines to which slot frame is transmitted.

Payload Length: indicates data size being transferred in the frame.

Header CRC: contains CRC computed from portion of Header Segment.

Cycle Count: holds value that increments for each comm. cycle start.

Data (Payload): contains data transferred by frame (254 bytes max.).

Trailer CRC: protects against improper header and payload modification.

FES (End of Frame): immediately follows the Trailer CRC

DTS (Dynamic Trailing Sequence): indicates a dynamic frame.

CID (Channel Idle Detection): indicates end of comm. (Idle: BP=BM)

Data_0: negative differential voltage between BP and BM.

Data_1: positive differential voltage between BP and BM.

Idle_LP (LowPower): biased to ground. No current to BP or BM.

Idle: biased to a voltage. No current to BP or BM.

BP (Bus Plus) and BM (Bus Minus) lines used to balance the differential

communications network.

FlexRay Bus Decode Terms

45

FlexRay Bus FlexRay Analysis Application

Configure :

Data Source Probing Trigger

46

Results :

Decoding CRC Analysis Correlation to Acq.-Mem


47

Results :

Timing Meas. Sync. Meas. Eye/Mask Test TIE Zoom


48


Real Signals

MASK violation

could be ID related

can lin flexray automotive seminar

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