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can_physical_layer:main [2015/04/14 09:38] – [Road vehicles -- ISO 11992-1] heinzcan_physical_layer:main [2018/08/21 23:09] (current) – external edit 127.0.0.1
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  {{http://www.oertel-halle.de/pic/canbus_level.png | CAN bus signal levels }}  {{http://www.oertel-halle.de/pic/canbus_level.png | CAN bus signal levels }}
  
-The picture shows the two signal states **recessive** and **dominant** and its signal levels for the CAN high speed version. +The picture shows the two signal states **recessive** and **dominant** and its signal levels for the CAN high speed version with 1 Mbit/sSince Dec 2016 ISO11898-2:2016 is published specifying bit rates above 1 Mbit/s 
 + 
  
  
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 The NXP application note [[ http://www.nxp.com/documents/application_note/AN10211.pdf|AN10211]] (TJA1040 high speed CAN transceiver) explains in detail the //Split termination concept// The NXP application note [[ http://www.nxp.com/documents/application_note/AN10211.pdf|AN10211]] (TJA1040 high speed CAN transceiver) explains in detail the //Split termination concept//
-===== Low Speed Fault Tolerant CAN -- ISO 11898-3 ====== 
  
-===== High Speed with low-power mode -- ISO 11898-5 ===== +==== High Speed with selective wake-up functionality ====
- +
-===== High Speed with selective wake-up functionality ISO 11898-6 =====+
  
 Karsten Penno explaining NXP CAN Partial Networking in a [[http://www.youtube.com/watch?v=8sU9ZWQNQY0|Youtube Video]] Karsten Penno explaining NXP CAN Partial Networking in a [[http://www.youtube.com/watch?v=8sU9ZWQNQY0|Youtube Video]]
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 The article "Energy saving in automotive electronics architectures", Thomas Liebetrau, Ursula Kelling, Tobias Otterer, Magnus Hell, all of them with Infineon Technologies AG, describes basics and application fields. Published "CAN Newsletter 4/2012, CiA. The article "Energy saving in automotive electronics architectures", Thomas Liebetrau, Ursula Kelling, Tobias Otterer, Magnus Hell, all of them with Infineon Technologies AG, describes basics and application fields. Published "CAN Newsletter 4/2012, CiA.
  
-The ISO 11898-6 standard is now in the proof process and will be published before end of the year 2013.  
 =====  Road vehicles -- ISO 11992-1 ===== =====  Road vehicles -- ISO 11992-1 =====
  
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 [[CAN Transceivers]] are interfaces to the CAN controller and to the CAN bus. Its task is to adapt the logic level signals from the CAN controller to the signal levels on the CAN bus.   [[CAN Transceivers]] are interfaces to the CAN controller and to the CAN bus. Its task is to adapt the logic level signals from the CAN controller to the signal levels on the CAN bus.  
  
-Different physical Layers are described in various ISO 11898 Documents, see above+Different physical layers are described in various ISO 11898 Documents, see below
  
   * ISO11898-2 HighSpeed CAN   * ISO11898-2 HighSpeed CAN
   * ISO11898-3 LowSpeedFaultTolerant CAN   * ISO11898-3 LowSpeedFaultTolerant CAN
-  * ISO11898-5 LowPower 
-  * ISO11898-6 LowPowerSelectiveWakeUp 
  
-A common transceiver for the physical layer defined by ISO 11898-2 (high-speed) is NXP/Philips 82C250 and (improved version) 82c251+A common transceiver for the physical layer defined by ISO 11898-2 (high-speed) is NXP TJA1044GT. 
-CAN transceivers are tested by the [[http://www.cs-group.de/ | C&S group]] (Germany) using the GIFT/ICT CAN High-Speed Transceiver Conformance Test. The paper [[http://www.cs-group.de/MunichGroupServer/public/documents/dev_spec/CAN_HS_PL_Req_12.pdf High Speed CAN]] Specification, Requirements, Vehicle Manufacturers, explains the test in detail.+ 
 +CAN transceivers are tested by the [[http://www.cs-group.de/ | C&S group]] (Germany) using the GIFT/ICT CAN High-Speed Transceiver Conformance Test. The page [[https://www.cs-group.de/testing/conformance-tests/can-osi-1/ | Conformance Testing]] explains the test strategies in detail. Furthermore, the site includes a link to the newest version of the "**Interoperability test specification for high-speed CAN transceiver or equivalent devices**".
    
 Other transceivers are TJA1054 for ISO 11898-3 (low-speed fault-tolerant CAN FaultTolerantCAN) and AU5790 (for SAE J2411 single-wire CAN). Other transceivers are TJA1054 for ISO 11898-3 (low-speed fault-tolerant CAN FaultTolerantCAN) and AU5790 (for SAE J2411 single-wire CAN).
  
-More information about different physical layers are available at [[http://www.can-cia.org/index.php?id=88|CiA]].+More information about different physical layers is available at [[http://www.can-cia.org/can-knowledge/can/systemdesign-can-physicallayer/|CiA]].
  
 The question: "Are there any compatibility problems with using a mixed 3.3V and 5V transceiver network?" was answered by Steve Corrigan s-corrigan1@ti.com: "I have a bus with 30 3.3-V HVD230s and 30 5-V 82C250s and have no problems." The question: "Are there any compatibility problems with using a mixed 3.3V and 5V transceiver network?" was answered by Steve Corrigan s-corrigan1@ti.com: "I have a bus with 30 3.3-V HVD230s and 30 5-V 82C250s and have no problems."
 +
 +Nowadays all micro controllers don't work anymore with 5V but 3.3V. To get ideas for the CAN bus transceiver designs in 3.3 V system read [[http://e2e.ti.com/blogs_/b/analogwire/archive/2016/10/18/top-five-reasons-to-use-3-3v-can-transceivers?hootPostID=f9f0ef82804f6aae5ea5cc1cad5be478 | Top five reasons to use 3.3V CAN transceivers]].
 +
  
 Some of the transceivers, e.g. NXP TJA1041, try to detect own problems by a feature called DOMINANT CLAMPING DETECTION. With this feature they introduce a low bit rate limit: TJA1041 Chapter TXD DOMINANT CLAMPING DETECTION: ..... The tdom(TXD) timer defines the minimum possible bit rate of 40 kbit/s. Other namings are **Dominant Timeout**.\\ The dominant time-out circuit prevents the driver from blocking network communications if a local CAN controller fault occurs. The time-out circuit is triggered by a falling edge on TXD. If no rising edge occurs on TXD before the time-out of the circuits expires, the driver is disabled to prevent the local node from continuously transmitting a dominant bit. If a rising edge occurs on TXD, commanding a recessive bit, the timer will be reset and the driver will be re-enabled. The time-out value is set so that normal CAN communication will not cause the dominant time-out circuit to expire. Some of the transceivers, e.g. NXP TJA1041, try to detect own problems by a feature called DOMINANT CLAMPING DETECTION. With this feature they introduce a low bit rate limit: TJA1041 Chapter TXD DOMINANT CLAMPING DETECTION: ..... The tdom(TXD) timer defines the minimum possible bit rate of 40 kbit/s. Other namings are **Dominant Timeout**.\\ The dominant time-out circuit prevents the driver from blocking network communications if a local CAN controller fault occurs. The time-out circuit is triggered by a falling edge on TXD. If no rising edge occurs on TXD before the time-out of the circuits expires, the driver is disabled to prevent the local node from continuously transmitting a dominant bit. If a rising edge occurs on TXD, commanding a recessive bit, the timer will be reset and the driver will be re-enabled. The time-out value is set so that normal CAN communication will not cause the dominant time-out circuit to expire.

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