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LIN decoding not reliable

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LIN decoding not reliable

Postby ge75el » Tue Oct 28, 2014 8:58 pm

Hello,

the current Version detects 20.41 kbaud instead of 19.2 kbaud on a LIN Signal.
When measurig the baudrate manually in the burst, I got 19.2 kbaud.
Even when correcting the baudrate manually to 19.2 kbaud it is not possible to decode the signal correctly. For example an end of frame was detected on a 0xFF sometimes.
An example is attached.
I can remember that older versions were more reliable in decoding.
Can anyone help me?

Regards, Georg
Attachments
20141028-02-LIN.psdata
LIN trace
(504.91 KiB) Downloaded 63 times
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Re: LIN decoding not reliable

Postby Hitesh » Wed Oct 29, 2014 10:38 am

Hi ge75el,

I have added your comments and psdata file to an existing bug report in relation to LIN decoding.

Have you tried the PicoScope 6.10 Beta?

Regards,
Hitesh

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Re: LIN decoding not reliable

Postby ge75el » Wed Oct 29, 2014 11:49 am

Hi Hitesh,

the current 6.10 Beta has the same problem.
I think I was around one year ago, when LIN Decoding was implemented as beta, where I had no problems.

Regards, Georg
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Re: LIN decoding not reliable

Postby Vojtech » Thu Oct 30, 2014 7:06 am

Hi ge75el,

I'm facing the same problem. Go into advanced settings and disable the Invert Packet Bits. This will cause to decode the data right. Unfortunatelly the GUI is somehow awkward and its hard to read the received bytes, because there are like:

ABCDEFGH instead of AB CD EF GH.

Vojtech

PS: disabling the Invert Packet Bits causes to decode the Sync wrong. :-/ So it seems to be a bug.
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Re: LIN decoding not reliable

Postby ge75el » Fri Oct 31, 2014 8:16 am

Hi Vojtech,

disabling Invert Packet Bits works a little bit but as you wrote, sync detection does not work correctly. So it is not possible to check the checksum of all frames via pressing Statistics button in the Serial Decoding window.

I think, we should start with the question why the Auto Detect of the baudrate does not work. It should be simple to calculate the baudrate out of the Sync. My Sync has 572.3 us and 11 pulses and this is 11 / 572.3 = 19.22 kBd which is exactly the expected value. Dont know why Lin Decoding calculates 20.41 kBd, which is 6 % higher.

Georg
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Re: LIN decoding not reliable

Postby ge75el » Fri Oct 31, 2014 12:34 pm

It seems also that the Lin Decoding here ignores the Break which is an active low signal for 13 clocks (= 677 us at 19.2 kBd). Here, a Lin frame can start also without having this Break signal.
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Re: LIN decoding not reliable

Postby Hitesh » Mon Nov 17, 2014 10:44 am

Hi Vojtech and Georg,

Just a message to let you know that your comments have been passed on to the Development Team for further investigation.

Regards,
Hitesh

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Re: LIN decoding not reliable

Postby ge75el » Wed Nov 26, 2014 12:35 pm

Hi Hitesh,

do you know if / when a fix could be expected?

Regards, Georg
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Re: LIN decoding not reliable

Postby Hitesh » Fri Nov 28, 2014 10:07 am

Hi Georg,

I've requested an updated from our Development Team.

I'll post an update once further information has been received.

Many thanks,
Hitesh

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Re: LIN decoding not reliable

Postby ge75el » Wed Jan 14, 2015 12:57 pm

Any new Information?
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Re: LIN decoding not reliable

Postby Hitesh » Thu Jan 15, 2015 1:54 pm

Hi Georg,

Apologies, no update at this moment in time.

There was a review of the Serial Decoding feature a few months ago with some rework identified. The reworked Serial Decoding should be available via a Beta release of the software but we do not have any timescales at present.

Have you tried setting both Threshold 1 and Threshold 2 in the Serial Decoding dialog?

Regards,
Hitesh

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Re: LIN decoding not reliable

Postby ge75el » Fri Jan 16, 2015 12:00 pm

Hi Hitesh,

I made some experiments with the Thresholds but it does not help.

Looking at attached LinTrace.png, I had no idea why the decoding starts a new frame EA:1E without having a break or burst before.

Regards,
Georg
Attachments
LinTrace.png
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Re: LIN decoding not reliable

Postby Hitesh » Mon Jan 19, 2015 3:09 pm

Hi Georg,

Can you send the corresponding data file to support@picotech.com please?

I can then pass this on to our Development Team for further investigation if required.

Changes have been made to the LIN decoder which should appear in a future Beta release of the software (no timescales as to when this will be available).

Regards,
Hitesh

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Re: LIN decoding not reliable

Postby ge75el » Thu Feb 05, 2015 10:47 pm

Hi Hitesh,

I want to check an older version (PicoScope6_r6_7_13.exe) for LIN decoding. I can remember that in former times, when LIN decoding was implemented 'Beta', it worked OK.
My problem is that this version refuses to open the .psdata file because it was too new. Is there a possibility to convert?

Regards,
Georg
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Re: LIN decoding not reliable

Postby ge75el » Fri Feb 06, 2015 8:55 am

PicoScope6_r6_8_10.exe was the last working version I found in my archive but also here it was not possible to read a .psdata file from 6.10 version.
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