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There are autosar specs well defined for CAN,LIN,Ethernet. Why are these specs unavailable for UART and I2C? Is UART and I2C not used in automotive?

AlphaGoku
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Automotive has some unique safety requirements and it would be hard to implement them in such protocols as UART or I2C.

They are not used by the auto industry for inter-ECU communication and therefore they are not part of the standard.

Adam Horvath
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  • Need not be inter ECU. What if my ECU has 2 controllers and both need to exchange PDU's. This can only be done via CDD in that case then ? – AlphaGoku May 20 '19 at 16:54
  • So their SWCs are implemented inside CDD layer? or they are never used at all ? – Mohamed Atef May 07 '22 at 12:28
  • According to @kesselhaus's comment you can support such protocols via finding (developing?) a unique implementation of LIN driver. It must be an easier approach then as a CDD module. – Adam Horvath May 09 '22 at 16:44
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Correct. As per AUTOSAR no specs are mentioned for the I2C. So if you want to write an I2C, you can write in CDD layer.

Yex
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The LIN Driver could be used also for SCI/UART:

[SWS_Lin_00063] ⌈It is intended to support the complete range of LIN hardware from a simple SCI/UART to a complex LIN hardware controller. Using a SW-UART implementation is out of the scope. For a closer description of the LIN hardware unit, see chapter 2.3.⌋(SRS_Lin_01547)

In the automotive field, I2C is not much used, even on-board. It might be easy and cheap, but its not as fast, not so safe (EMC/noise), and you could even block the whole bus with all nodes, if a slave pulls the SDA low.

A lot of interface chips are using SPI, and for this, we have the SPI driver.

kesselhaus
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    I would appreciate a link to an analysis why I2C has more EMC issues than SPI. I already tried Google, but did not find a comparison. – Torsten Knodt Jan 06 '20 at 17:23