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JohnMan
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Hello dear sirs,

I am currently using TLE9879 MCU. Could you share with me the interface design for PWM & LIN communication? In datasheet, I cannot find which port can be used for PWM signal output. Bus seems like PWM can share the same LIN port as input port. is it true? Per HW design guideline, if using PWM, a resistor greater than 1Kohm need to be connected between LIN and Vs. Does it mean when for LIN communication this resistor need to be removed  and for PWM communication this resistor need to be connected?  Any other considerations?

Thanks

John

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Raj_JC
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Hi @JohnMan,

Please, find my response to your questions as following:

  1. Could you share with me the interface design for PWM & LIN communication?

       >> Please, refer to the schematic design of the TLE9879 EVALKIT.

       2. In datasheet, I cannot find which port can be used for PWM signal output. Bus seems like PWM can share the same LIN port as input port. is it true?

      >> Please, refer to the Capture/Compare Unit 6 (CCU6) in the datasheet for PWM output.

     3) Per HW design guideline, if using PWM, a resistor greater than 1Kohm need to be connected between LIN and Vs. Does it mean when for LIN communication this resistor need to be removed  and for PWM communication this resistor need to be connected? 

         >> Please, refer to the schematic design of the TLE9879 EVALKIT. It is recommended to connect 1k Ohm for                 the PWM configuration but there is no need to disconnect it for the  LIN communication

            4) Any other considerations?

           >> It is recommended to put a 220 pF capacitor between the LIN and the GND_LIN pins. This complies with the LIN specification 2.2. The GND_LIN pin has to be connected to a global round net outside of the chip.

           >> For other recommendations please follow Hardware design guideline

Please, let us know if you need further support.

Thank you

Best Regards

Raj Chaudhari

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Raj_JC
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Moderator 250 sign-ins 25 likes received 50 solutions authored
Moderator

Hi @JohnMan,

Please, find my response to your questions as following:

  1. Could you share with me the interface design for PWM & LIN communication?

       >> Please, refer to the schematic design of the TLE9879 EVALKIT.

       2. In datasheet, I cannot find which port can be used for PWM signal output. Bus seems like PWM can share the same LIN port as input port. is it true?

      >> Please, refer to the Capture/Compare Unit 6 (CCU6) in the datasheet for PWM output.

     3) Per HW design guideline, if using PWM, a resistor greater than 1Kohm need to be connected between LIN and Vs. Does it mean when for LIN communication this resistor need to be removed  and for PWM communication this resistor need to be connected? 

         >> Please, refer to the schematic design of the TLE9879 EVALKIT. It is recommended to connect 1k Ohm for                 the PWM configuration but there is no need to disconnect it for the  LIN communication

            4) Any other considerations?

           >> It is recommended to put a 220 pF capacitor between the LIN and the GND_LIN pins. This complies with the LIN specification 2.2. The GND_LIN pin has to be connected to a global round net outside of the chip.

           >> For other recommendations please follow Hardware design guideline

Please, let us know if you need further support.

Thank you

Best Regards

Raj Chaudhari

JohnMan
Level 1
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Hello Mr. Raj Chaudhari,

Thank you for your reply. So you mean PWM can share LIN interface for both input and output just with 1kohm resistor pull up to VS, correct?

But for LIN slave, a 30Kohm has to be connected to Vs just like Rbus inside the chip. If the 1Kohm resistor is not going to be removed, it will be in parallel with the 30Kohm. This will lead to LIN slave not in compliance with LIN spec.. 

Which page of  TLE9879 EVALKIT I can refer to for the PWM signal share with LIN interface?  

Thanks

John

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Raj_JC
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Hi @JohnMan,

Please, refer to the Jumper settings in the TLE9879 EvalKit User Manual.

 

Raj_JC_1-1662540136188.png

For schematic you can refer to the Page no:13 of the same user manual.

Please, let us know if you need further support.

Thank you

Best Regards

Raj Chaudhari

 

 

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JohnMan
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Hello Mr. Raj Chaudhari,

The jumper is used for LIN master and slave, but I need PWM signal share with LIN interface. Do you mean LIN master configuration can be used for PWM signal transmission and receive? 

Thanks

Best regards

John

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Raj_JC
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Moderator

Hi @JohnMan,

Could you please let me know if you want to use the LIN and PWM together or either of them at a time? If the implementation is the first case (LIN and PWM together) then it is not possible.

1) For LIN only: Configure Jumper settings for the LIN Master/Slave config.

2) For PWM: Refer to the TLE9879 PWM+LIN InterfaceTLE9879 PWM Interface examples  for capturing the PWM signal at LIN using the Timer 2.

Please, let us know if we understood your implementation correctly.

Thank you 

Best Regards

Raj Chaudhari

JohnMan
Level 1
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Level 1

Hello Mr. Raj Chaudhari,

I want to use the LIN and PWM  either of them at a time. Could you share with me the HW design?If you do not have a reference design, pls just answer my concerns regarding the interface design in the chain. Pls note that TLE9879 is not LIN master but always LIN slave. So I do not think the 1Kohm pull up resistor is correct. I also doubt why not use the Rbus(30kohm) inside TLE9879 LIN interface for PWM signal transmission?

Thanks

John 

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Raj_JC
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Hi @JohnMan,

1) For selecting the Master or Slave configuration please use an external switch to connect (For Master) or disconnect (For Slave) external 1k Ohm.

2) For PWM signal transmission there is no need for the external 1k Ohm pullup as it is taken care by the LIN transceiver block. 

Raj_JC_0-1663580124482.png

>>  For the reference design you can refer to the section 10 Schematics and Layout of the TLE9879 EvalKit V1.4 User Manual .

Please, let us know if you need further support.

Thank you

Best Regards

Raj Chaudhari

JohnMan
Level 1
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Hello Mr. Raj Chaudhari,

1) I use LIN slave only, no LIN master.

2) It is specified in Infineon HW design guideline to use 1Kohm pull up resistor for PWM signal transmission. Pls see below wording from this Design note:

The LIN transceiver can be used also with PWM control. In this case, a pull-up resistor between the LIN input and the battery input voltage should be placed. The value of the pull-up resistor is ≥ 1 kΩ.

It is contradictory from your description. Pls confirm again.

3) Based on your latest input, seems like only a 220pF is needed between LIN and GND for either LIN slave or PWM transmission from HW point of view. Pls confirm.

Thanks

John

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Raj_JC
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Hi @JohnMan,

Sorry for overlooking the fact mentioned in your second point. Yes, please follow the Hardware design guide for the PWM control, and for connecting an external pull-up you can follow my first recommendation of the dynamic connection.

Thank you

Best Regards

Raj Chaudhari

JohnMan
Level 1
5 replies posted 5 sign-ins 5 likes given
Level 1

Raj Chaudhari,

You have not answered my concerns. I do not think you are HW engineer. I repeated my points again and again but you lost my points again an again. You even gave me a wrong answer. I do not know how to communicate with you furthermore. You provided the worst engineering service I have seen in my 30+ EE years!

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Viswa
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Hi

I consolidated the queries raised and the response, please let me know if any further details are required

 

  • Recommendations to use LIN in slave mode
  1. CLIN --> Filter capacitor at LIN pin –-> 220pF, to be connected between LIN and GND_LIN
  2. Please follow Page 21 of Hardware Design GuideLine document.
  3. To use LIN in slave mode 1k Ohm Pull-up is not required.

 

  • To use PWM on LIN channel
  1. When LIN transceiver is used for PWM control, a pull-up resistor between the LIN input and the battery input voltage should be placed. The value of the pull-up resistor is ≥ 1 kΩ. The 220pF connected may remain connected in this mode as well.
  2.  Refer to the TLE9879 PWM+LIN Interface, TLE9879 PWM Interface examples  for using LIN transceiver to detect a PWM signal.

 

Best Regards,

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JohnMan
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Hi,

To use PWM on LIN channel, a pull-up resistor between the LIN input and the battery input voltage should be placed. The value of the pull-up resistor is ≥ 1 kΩ. So I can place 1kohm or any other resistor which value is more than 1kohm, suppose it is 30kom. If so, why not use RBUS(30Kohm) inside LIN transceiver of TLE9879?

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Viswa
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Hi @JohnMan 

If so, why not use RBUS(30Kohm) inside LIN transceiver of TLE9879?

The 30Kohm resistor is internal to the chip, it is required to have a pull-up resistor externally.
As a recommendation please use 1Kohm. 

Best Regards

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JohnMan
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Hi Viswa,

Can you let me know why an external 1kohm resistor is recommended , not from HW design guideline document point of view but from circuit design point of view?

Adding an external 1kohm resistor is easy for me but when when the LIN port is configured for LIN slave  application, I have to remove this resistor because LIN slave requests 30kohm pull up to Vbat. 

Best regards

John

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Viswa
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Hi @JohnMan 

 


Can you let me know why an external 1kohm resistor is recommended , not from HW design guideline document point of view but from circuit design point of view?


 This is a part of the chip design and hence the recommendation is provided in the HW design guideline.


Adding an external 1kohm resistor is easy for me but when when the LIN port is configured for LIN slave  application, I have to remove this resistor because LIN slave requests 30kohm pull up to Vbat. 


We agree with you, if you would like to use the processor in both modes PWM and LIN slave, you may have to use a switch to disconnect the 1K from the circuit.

 

Best Regards