S32K LIN issue

[linton]

HI NXP team,

I use the S32K148 LIN driver, the setting  is master and baud rate is 19200 as below picture show:

and the content I send are:   the LIN ID: 0x0C;    service is transmit message;   data length: 8

data: 0x17 0x06 0xff 0xff 0xff 0xff 0xff 0xff;

I use the method as below:

1. send the header first: 

2. then in the callback function: send the content:

now the problem happen, I use the oscilloscope to check the wave, it looks different with the standard machine(ExxoTEST,  third party machine). as below show:

the R2 channel( the top wave) is Exxotest send data wave

the C1 channel(the middle wave) is the third party send data wave

the R1 channel(the bottom wave)is the NXP S32K 148 send data wave

the R2 and C1 channel are almost the same, so I think this waveform is right.

the S32K 148 LIN send data looks not right. Do you have any idea what case this problem??

[PetrS]

Hi,

it seems data sent are similar, just bitrate is little bit slower. Check clock used for baud clock. If for example FIRC is selected, used rather SOSC.

BR, Petr

[linton]

Hi petrS,

I change the LPUART1_CLK as you recommend, see below photo:

the waveform is almost the same, did not have any improvement.

I also try the other 3 clock as below show:

the waveform almost the same, so I have to do next to fix this issue??

Thanks for you quick reply.

[PetrS]

Hi,

measure actual bitrate generated, compare with other tools. Share values programmed in LPUART registers.
Is some LIN analyzer able to decode a frame, are payload the same?

BR, Petr

[linton]

Hi PetrS,

measure actual bitrate generated, compare with other tools. Share values programmed in LPUART registers.
Is some LIN analyzer able to decode a frame, are payload the same?

1.The actual bitrate is slower than setting(19.2K);

2.Share values programmed in LPUART registers.  you mean in debug mode, show you the LPUART registers??

3. the LIN analyzer is able to decode the frame,  the payload is all the same.

Why I raise this issue,  because sometimes the S32K148 board as master node,  the slave node can not receive the content. Is it possible the sync field wave form not good then cause this issue??

[PetrS]

Hi,

I wanted to know exact bit time measured for generated signal and actual content of LPUART registers, to know bitrate setting.
If bitrate is different too much, then slave can have issue to sync to a frame. However frame is correct if it is properly detected by analyzer.

BR, Petr