The LIN communication issue using the FS6500 chip

[Aoyng]

Hello, currently I am using the LIN communication module based on the FS6500 chip, and the MCU is set to slave mode. I noticed that the LIN communication would be disconnected after a period of time. After referring to the FS6500 manual, I found that when the FS6500 acts as a LIN slave transceiver, the LIN bus pins do not require a 1KΩ resistor and a diode. However, when I looked at the engineering schematic, I noticed that there is a 1KΩ resistor and a diode at one end of the LIN bus. Could this affect my LIN communication? I look forward to your response. Thank you.

[danielmartynek]

Hi @Aoyng,

Can you specify the period of time? 

Do you monitor the bus with an oscilloscope?

What schematic do you mean? 

Thank you,

BR, Daniel

[Aoyng]

Hello, here's the situation. I reviewed the LIN section of the FS6500 manual and learned that when the LIN configuration of this chip is in slave mode, the external pins connected to the LIN bus do not require a 1kΩ resistor or a diode. However, in my hardware design circuit diagram, I have designed a 1kΩ resistor and a diode. So I'm wondering if this will have an impact on the communication. And I'm the person who replied to your post about restoring other LIN communication issues yesterday. Because the current LIN communication will disconnect after a period of time, and I have no clue at the moment. That's why during the troubleshooting process, I came across the relevant design of FS6500, suspecting if it's a hardware problem. I'm looking forward to your further understanding of my LIN communication issue in other posts and by combining this post. I'm grateful and looking forward to your help, as it's very important to me.This is the question I raised for you in another post. You can take a look at it. These are all issues resulting from one problem. The post title:The S32K314 uses the LPUART to configure as a LIN slave communication interrupt.

[danielmartynek]

Hello @Aoyng,

I have just replied in the other thread you mentioned:
https://community.nxp.com/t5/S32K/The-S32K314-uses-the-LPUART-to-configure-as-a-LIN-slave/m-p/236597...

The presence of the diode and pull-up resistor can indeed contribute to the framing errors you are observing on the LIN bus.

Could you try removing these components from the PCB (or isolating them) and check if the issue persists?

BR, Daniel

[Aoyng]

Hello, I tried to remove the resistor but the problem of the LIN communication disconnecting still exists. Judging from this, it seems to have nothing to do with the current hardware. Let's continue to investigate from other aspects, such as my other posts. Thank you for your help.