[SOLVED] Requirement of CAN transceiver in automotive interface

[ChansAlive]

Hi

There are many micro controller which has an in-built CAN module present in it(example: dsPIC33F etc). But is it just enough to interface with the CAN bus in the automotive environment? Do we require a transceiver module in between to have better fault tolerant and to meet specification? Please help me to know whether a transceiver is necessary in most of the interface like CAN, LIN and K-Line(KWP2000, ISO9141).

Hope someone could help me...

 

[yura717]

https://www.linear.com/product/LT1796

 

[ChansAlive]

@yura717
Hi thanx for the link... But I think you didn't understand my question. I'm asking whether it is mandatory to use a transceiver in automotive interfaces...

 

[yura717]

you can check how much electrical noise from welding equipment I think its can affect CAN interface ....

 

[bigdogguru]

CAN physical layers like the ISO-11898-2/5 are typically of 12v to 24v differential implementations, which are also subject to shorts and high voltage transients.

Therefore a CAN transceiver like the MCP2561 or MCP2551 is required to provide an interface/bridge between the CAN physical layer and the logic levels of a microcontrollers CAN controller module.

Microchip CAN Transceivers

For comparable reasons, LIN Transceivers are also required to implement the physical layer of LIN Bus Specifications Version 1.3, 2.x and SAE J2602-2.

Microchip LIN Transceivers


BigDog

 

[ChansAlive]

@bigdogguru
Thanks very much... It answered my question. But can anyone explain what is the case for K-Line(KWP, ISO9141) interface? A transceiver is required there too?

 

[bigdogguru]

But can anyone explain what is the case for K-Line(KWP, ISO9141) interface? A transceiver is required there too?

The short answer to your question is, Yes.

Local Interconnect Network (LIN 2.x/SAEJ2602) and K-Line (ISO9141) are quite similar and share many of the same attributes, a similar specification is the Electrical Control Line (ECL) Specification of the Media Oriented Systems Transport (MOST) Network.

Both a single wire network, intend to operate in harsh environments, with voltages as high as +/- 40v.

As a matter of fact, several of the available LIN 2.x/SAEJ2602 Physical Interfaces/Transceivers also support K-Line (ISO9141):

**broken link removed**

Features

LIN Physical Layer Specification Revision 2.0 Compliant and Conforms to SAEJ2602 Recommended Practice for LIN
LIN Bus Speed up to 20-kbps LIN Specified Maximum and MOST ECL Speeds Down to 0 Baud
Supports ISO9141 (K-Line)
Qualified for Automotive Applications
...
...

SN65HVDA100 Datasheet

TPIC1021A Datasheet

BigDog

 

[bigdogguru]

But can anyone explain what is the case for K-Line(KWP, ISO9141) interface? A transceiver is required there too?

The short answer to your question is, Yes.

Local Interconnect Network (LIN 2.x/SAEJ2602) and K-Line (ISO9141) are quite similar and share many of the same attributes, a similar specification is the Electrical Control Line (ECL) Specification of the Media Oriented Systems Transport (MOST) Network.

Both a single wire network, intend to operate in harsh environments, with voltages as high as +/- 40v.

As a matter of fact, several of the available LIN 2.x/SAEJ2602 Physical Interfaces/Transceivers also support K-Line (ISO9141):

**broken link removed**

Features

LIN Physical Layer Specification Revision 2.0 Compliant and Conforms to SAEJ2602 Recommended Practice for LIN
LIN Bus Speed up to 20-kbps LIN Specified Maximum and MOST ECL Speeds Down to 0 Baud
Supports ISO9141 (K-Line)
Qualified for Automotive Applications
...
...

SN65HVDA100 Datasheet

TPIC1021A Datasheet



You might find the follow appnote of interest concerning the LIN Protocol:

LIN Protocol Implementation Using PICmicro MCUs



BigDog

 

[ChansAlive]

@BigDog..
Wonderful... Thanks very much... It did completely solve my questions...