WUP The new bus wake up concept Magnus-Maria Hell Infineon technologies
16th international CAN Conference in Nuremberg
Agenda
Current situation
New Wake up mechanism
New parameters
WUP and WUF
Supporting specifications
Summary
1
2
3
4
5
6
2 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Agenda
Current situation
New Wake up mechanism
New parameters
WUP and WUF
Supporting specifications
Summary
1
2
3
4
5
6
3 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Bus wake up behaviour
Current situation
› In the ISO 11898-5 the bus wake up behavior is described the first time
› This was not robust enough against noise and spikes for future needs
› A new wake up behavior is specified in the new ISO 11898-2:2016
A bus wake up shall be performed if the bus shows one or multiple consecutive dominant bus levels
for at least tFilter, each separated by a recessive bus level
4 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
ISO 11898-5 Wake up specification
A dominant level longer than 5 µs will be detected
Parameter Notation Min Max Unit Condition
CAN activity filter time tFilter 0,5 5 µs
A dominant level shorter than 500 ns will be ignored
Bus signals
CAN_H
CAN_L
CAN_H
CAN_L
5 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Frame format analyses
› CBFF (Classical base frame format)
RTR, IDE, FDF = dominant = 6µs; fulfills dominant bus levels condition for FBFF frames
S
O
F
4 bit
DLC 0-8 bytes 15 bit
CRC 11 bit Identifier
R
T
R DE
L I
D
E 7 3
Arbitration Field Control Field Data Field CRC Field
AC
K
EOF Int. Bus Idle
F
D
F
S
O
F
4 bit
DLC 0-8 bytes
15* bit
CRC 11 bit Identifier
S
R
R CR
C d
el
I
D
E 1 1 7 3
Arbitration Field Control
Field Data Field CRC Field ACK EOF Int.
R
T
R
18 bit Identifier
Extension
F
D
F
r
0
› CEFF (Classical extended frame format)
RTR, FDF, r0 = dominant = 6µs; fulfills dominant bus levels condition for FEFF frames
6 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Disadvantages
› Detailed specification for the flow were missing
o Precise definition of recessive level missing
o Precise definition of multiple missing
o Some implementation sensitive against spikes and noise in the bus
o Permanent short on the bus not covered
o Improvement needed
A bus wake up shall be performed if the bus shows one or multiple consecutive dominant bus levels
for at least tFilter, each separated by a recessive bus level
7 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Reason for unwanted wake up
Software failures
Physical Layer effects
o High transients coupled into the bus
=> Mode conversion ( recessive level become dominant)
o Worse twisting of the cable
o Long untwisted part at the end of the wire
o Asymmetric capacitive load on the wire
o Different wire length of CANH and CANL
o Common range of the receiver to small
The new wake up mechanism should be more robust
8 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Agenda
Current situation
New Wake up mechanism
New parameters
WUP and WUF
Supporting specifications
Summary
1
2
3
4
5
6
9 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
The new Wake Up Pattern Flow
Step 1: Transceiver entered low power mode
Bus biasing is off, device is in low power mode
Bus recessive; no communication
CAN bus activity detection unit is active
If Bus dominant > tFilter condition is fulfilled
=> Transceiver will jump to State 1
10 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Wake Up Pattern Flow
Step 2:
Communication on the bus
CAN Bus activity detection unit is active
If Bus recessive > tFilter condition is fulfilled
=>Transceiver will jump to State 2
11 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Wake Up Pattern Flow
Step 3:
Communication is running
CAN bus activity detection unit is active
If bus dominant > condition is fulfilled
=>Transceiver will jump to State 3
In State 3
o Transceiver is woken up
o Bus biasing is switched on.
12 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Wake Up Pattern Flow
State 3 and 4:
Communication is running
During communication cycling between State 3 and 4
independent of the transceiver mode
( low power mode or normal mode)
In case of Bus silence Transceiver wait in State4
In low power mode and tsilence expired
=>Transceiver moves to State INI
=> The next CAN Frame will wake up again
13 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Wake Up Pattern with a CAN FD Frame
No dedicated Wake up pattern is needed
Every Device will be woken up with 1 or 2 CAN FD frames
With the short filter time CAN FD with 29Bit ID is covered
Step 1: dominant condition detection
Step 2: recessive condition detection
Step 3: dominant condition detection
14 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Wake Up Pattern Flow
Permanent dominant in State 1
Caused by a short CANH to Battery
In State 1 twake timer will be active
If twake is expired (> 800µs)
=>Device will change into State WAIT as long as the bus is dominant
If the permanent dominant is recovered and
bus recessive > tFilter
=>Device changes back into State Ini
After permanent dominant longer than twake,
the Transceiver moves into State Ini and not into State 2
15 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Wake Up Pattern Flow
Dominant spikes coupled into the bus
A spikes drive the transceiver into State 1
The following recessive phase drives the transceiver into State 2
In State 2 twake timer will be active
After twake is expired (> 800µs)
=>Mode change back to mode INI
Two dominant pulses with a distance longer than twake
will not cause a wake up
16 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
CAN FD Frame format analyses
› FBFF (CAN FD base frame format)
S
O
F
4 bit
DLC 0-64* bytes
17 or 21
bit
CRC 11 bit Identifier
R
R
S
I
D
E 1 1 7 3
Arbitration Field Control Field Data Field CRC Field ACK EOF Int. Bus Idle
B
R
S
E
S
I
F
D
F
r
e
s
4 bit
Stuff
Count
DE
L
› FEFF (CAN FD extended frame format)
S
O
F
4 bit
DLC 0-64* bytes
17 or 21
bit
CRC 11 bit Identifier
S
R
R CR
C d
el
I
D
E 1 1 7 3
Arbitration Field Control Field Data Field CRC Field ACK EOF Int.
R
R
S
18 bit Identifier
Extension
E
S
I
F
D
F
B
R
S
r
e
s
4 bit
Stuff
Count
RRS, IDE = dominant < 6µs ; dominant condition (tFilter = 5µs max) is not fulfilled
In the protocol the dominant bus level condition (tFilter = 5µs max) is not fulfilled
D
D For CAN FD tFilter = 1,8µs max is needed
18 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
CAN FD Frame format analyses
› FBFF (CAN FD base frame format)
S
O
F
4 bit
DLC 0-64* bytes
17 or 21
bit
CRC 11 bit Identifier
R
R
S
I
D
E 1 1 7 3
Arbitration Field Control Field Data Field CRC Field ACK EOF Int. Bus Idle
B
R
S
E
S
I
F
D
F
r
e
s
4 bit
Stuff
Count
DE
L
› FEFF (CAN FD extended frame format)
S
O
F
4 bit
DLC 0-64* bytes
17 or 21
bit
CRC 11 bit Identifier
S
R
R CR
C d
el
I
D
E 1 1 7 3
Arbitration Field Control Field Data Field CRC Field ACK EOF Int.
R
R
S
18 bit Identifier
Extension
E
S
I
F
D
F
B
R
S
r
e
s
4 bit
Stuff
Count
RRS, IDE = dominant > 1,8 µs ; dominant condition (tFilter = 1,8µs max) is not fulfilled
In the protocol the dominant bus level condition (tFilter = 1,8µs max) is fulfilled
D
D
With tFilter = 1,8µs all CAN Frames wakes up 19 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Agenda
Current situation
New Wake up mechanism
New parameters
WUP and WUF
Supporting specifications
Summary
1
2
3
4
5
6
20 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
ISO 11898-2 Wake up Pattern
› New ISO specification for CAN activity filter time
Parameter Notation Min Max Unit Condition
CAN activity filter time, long Vdiff= VCAN_H - VCAN_L
tFilter 0,5 5 µs 1,2V ≤ Vdiff ≤ 3V -10,8V ≤ VCAN_H ≤ 12,0V -12,0V ≤ VCAN_L ≤ 10,8V
CAN activity filter time, short tFilter
0,15 1,8 µs 1,2V ≤ Vdiff ≤ 3V
-10,8V ≤ VCAN_H ≤ 12,0V -12,0V ≤ VCAN_L ≤ 10,8V
Wake up time, short tWake
800 10000 µs
Optional parameter
Timeout for bus inactivity tSilence
600 1200 ms Time is reset and restarted,
when bus changes from dominant to recessive or
vise versa
› With the add parameter CAN activity filter time , short bit rates up to 500kBit/s
can be used for bus (remote) wake up)
21 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
The filter times and the OEMs
tFilter short
tFilter long
150ns 1800ns
500ns 5000ns
TLE9251VSJ/VLE
TLE9252VSK/VLC
TLE9250SJ/LE/VSJ/VLE/XSJ/XLE
TLE9461/71 (-3)ES (V33)
TLE9260/1/2/3 (-3)QX (V33)
TLE9270/1/2/3 (-3)QX (V33)
TLE9255WSC/WLC
Supports Remote wake up feature
Supports all Wake up filter time requirements
Supports 5MBit/s
IOPT Reference Device
Fully ISO11898-2 ed2016 Compliant
Support CAN PN with CAN FD tolerance
Preferred of the most of the OEMs
Preferred of US OEMs to be robust against noise
to cover CAN FD
22 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Agenda
Current situation
New Wake up mechanism
New parameters
WUF and WUP
Supporting specifications
Summary
1
2
3
4
5
6
23 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
WUF and WUP
› WUF (Wake up Frame)
WUF is a dedicated classical CAN Frame with a defined ID
WUF wakes up a Partial Network transceiver in selective wake mode
› WUP and Partial Network transceiver
– WUP used in low power mode with selective wake up disabled
o Depends on the implemented tFilter time classical CAN or CAN FD frames can be used for a wake up
– WUP used in low power mode with selective wake up enabled
o Transceiver in selective wake mode
o Bus silence (no communication on the bus) longer than 1,2 s
o WUP mechanism (CAN communication) restarts selective wake mode
24 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Agenda
Current situation
New Wake up mechanism
New parameters
WUP and WUF
Supporting specifications
Summary
1
2
3
4
5
6
25 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
ISO 11898-2
ISO 11898-2 (2003)
Physical Layer
Communication
ISO 11898-5 (2007)
Physical Layer
Communication
+ Remote Wake up
ISO 11898-6 (2013)
Physical Layer
Communication
+ Remote Wake up
+ Partial Network
ISO 11898-2 (2016)
Physical Layer
Communication
+ Remote Wake up
+ Partial Network
+ CAN FD
26 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
CAN FD USER Documents
ISO 11898-2 (2016)
Network topology
CAN controller Set up
(Time quanta, Sample Point)
ECU
requir
em
ents
CAN
FD
contro
ller
require
ments
SAE specifications (updated in 2016)
SAE 2284-1 Guideline up to 125kBit/s
SAE 2284-2 Guideline up to 250kBit/s
SAE 2284-3 Guideline up to 500kBit/s
SAE 2284-4 Guideline up to 2000kBit/s
SAE 2284-5 Guideline up to 5000kBit/s
CAN in Automation
ISO 11898-1 (2015)
CiA 601-1 (released and updated)
Physical interface implementation
CiA 601-2 : Controller interface recommendation
CiA 601-3 : System Design recommendation
CiA 601-4 : Ringing suppression
CiA 601-5: Reference topologies
27 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
CAN FD data link Layer and higher
ISO 11898-1(2015)
AutoSar 4.1 And higher
CiA 601-2 CiA 601-3
Automotive (Passenger cars)
Commercial Vehicle
CiA 602-2
Industrial
CiA 30x CiA 40x
28 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
CAN FD Physical Layer
ISO 11898-2(2016)
SAE J2284-4 SAE j2284-5
CiA 601-1
Automotive (Passenger cars)
Commercial Vehicle
CiA 602-1
Industrial
CiA 601-5
29 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Agenda
Current situation
New Wake up mechanism
New parameters
WUP and WUF
Supporting specifications
Summary
1
2
3
4
5
6
30 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.
Summary
› The new WUP wake up mechanism guarantee a more reliable bus wake up mechanism
› All classical CAN and CAN FD frames supports remote wake up
› No dedicated wake up Frame needed
› The tightened range 500ns to 1800ns covers OEMs req. world wide
› All these parameters are specified in the new ISO 11898-2:2016
31 2016-03-07 Copyright © Infineon Technologies AG 2017. All rights reserved.