WUP The new bus wake up concept - can-cia.org

1 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.

2 All rights reserved. ISO 11898-5 wake up specification A dominant level longer than 5 s will be detected Parameter Notation Min Max Unit Condition CAN activity filter time tFilter 0,5 5 s 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 = 6 s; 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 DEL I D E 7 3 Arbitration Field Control Field Data Field CRC Field ACK EOF Int. Bus Idle FDF S O F 4 bit DLC 0-8 bytes 15* bit CRC 11 bit Identifier S R R CRC del 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 = 6 s; fulfills dominant bus levels condition for FEFF frames 6 2016-03-07 Copyright Infineon Technologies AG 2017.

3 All rights reserved. Disadvantages Detailed specification for the flow were missing oPrecise definition of recessive level missing oPrecise definition of multiple missing oSome implementation sensitive against spikes and noise in the bus oPermanent short on the bus not covered oImprovement 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 oHigh transients coupled into the bus => Mode conversion ( recessive level become dominant) oWorse twisting of the cable oLong untwisted part at the end of the wire oAsymmetric capacitive load on the wire oDifferent wire length of CANH and CANL oCommon range of the receiver to small The new wake up mechanism should be more robust 8 2016-03-07 Copyright Infineon Technologies AG 2017.

4 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 oTransceiver is woken up oBus biasing is switched on.

5 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 29 Bit 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.

6 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 (> 800 s) =>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 (> 800 s) =>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.

7 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 DEL 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 CRC del 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 < 6 s ; dominant condition (tFilter = 5 s max) is not fulfilled In the protocol the dominant bus level condition (tFilter = 5 s max) is not fulfilled D D For CAN FD tFilter = 1,8 s max is needed 18 2016-03-07 Copyright Infineon Technologies AG 2017. All rights reserved.

8 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 DEL 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 CRC del 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 s ; dominant condition (tFilter = 1,8 s max) is not fulfilled In the protocol the dominant bus level condition (tFilter = 1,8 s max) is fulfilled D D With tFilter = 1,8 s 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.

9 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 s 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 s 1,2V Vdiff 3V -10,8V VCAN_H 12,0V -12,0V VCAN_L 10,8V wake up time, short tWake 800 10000 s 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 TLE9251 VSJ/VLE TLE9252 VSK/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) TLE9255 WSC/WLC Supports Remote wake up feature Supports all wake up filter time requirements Supports 5 MBit/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.

10 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 oDepends 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 oTransceiver in selective wake mode oBus silence (no communication on the bus) longer than 1,2 s oWUP mechanism (CAN communication) restarts selective wake mode 24 2016-03-07 Copyright Infineon Technologies AG 2017.