s12zvl LIN cammunication is not working

[charudattaingal]

Hello Team,

I gave the 6.1 volt input to s12zvl Micro due to some ignition circuitry actual available voltage on Vsup pin ( pin no 1 ) is  5.79v.

I observed LIN  Communication is not working, I believe Internal voltage regulator and LIN phy still work because voltage is more than 5.5 v available on pin.

Please suggest, want to find out why LIN communication is not working when voltage available on Vsup pin is 5.70

If voltage on vsup pin is greater than 6V micro is communicating over LIN.

[RadekS]

Hi Charudatta,

Could you please let me know how you test whether LIN communication is working or not (what is detector)?

Idea: I can imagine a case when you create lin bus with S12ZVL MCU powered by the regulated voltage regulator and with some another LIN node powered from 12V. When you decrease MCU power supply down to 12V/2=6V, even MCU recessive state will be detected as dominant since another LIN node is still powered from 12V with a threshold close to VBAT/2.

Please check whether both nodes are powered by similar voltage level and watch LIN data directly by an oscilloscope.

I hope it helps you.

Have a great day,
Radek

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