LIN decoding not reliable

Forum for discussing PicoScope version 6 (non-automotive version)
ge75el
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Joined: Wed Feb 29, 2012 7:42 pm

LIN decoding not reliable

Post by ge75el »

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 506 times

Hitesh

Re: LIN decoding not reliable

Post by Hitesh »

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,

ge75el
Newbie
Posts: 0
Joined: Wed Feb 29, 2012 7:42 pm

Re: LIN decoding not reliable

Post by ge75el »

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

Vojtech
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Joined: Wed Oct 29, 2014 1:33 pm

Re: LIN decoding not reliable

Post by Vojtech »

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.

ge75el
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Posts: 0
Joined: Wed Feb 29, 2012 7:42 pm

Re: LIN decoding not reliable

Post by ge75el »

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

ge75el
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Joined: Wed Feb 29, 2012 7:42 pm

Re: LIN decoding not reliable

Post by ge75el »

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.

Hitesh

Re: LIN decoding not reliable

Post by Hitesh »

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,

ge75el
Newbie
Posts: 0
Joined: Wed Feb 29, 2012 7:42 pm

Re: LIN decoding not reliable

Post by ge75el »

Hi Hitesh,

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

Regards, Georg

Hitesh

Re: LIN decoding not reliable

Post by Hitesh »

Hi Georg,

I've requested an updated from our Development Team.

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

Many thanks,

ge75el
Newbie
Posts: 0
Joined: Wed Feb 29, 2012 7:42 pm

Re: LIN decoding not reliable

Post by ge75el »

Any new Information?

Hitesh

Re: LIN decoding not reliable

Post by Hitesh »

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,

ge75el
Newbie
Posts: 0
Joined: Wed Feb 29, 2012 7:42 pm

Re: LIN decoding not reliable

Post by ge75el »

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

Hitesh

Re: LIN decoding not reliable

Post by Hitesh »

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,

ge75el
Newbie
Posts: 0
Joined: Wed Feb 29, 2012 7:42 pm

Re: LIN decoding not reliable

Post by ge75el »

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

ge75el
Newbie
Posts: 0
Joined: Wed Feb 29, 2012 7:42 pm

Re: LIN decoding not reliable

Post by ge75el »

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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