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4227 - LIN Logic Analysis

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4227 - LIN Logic Analysis

Postby Vojtech » Thu Oct 30, 2014 6:53 am

Hello guys,

I'm using the 4227 PicoScope with SW version 6.9.18.1. I'm measuring data over LIN bus and I wanted to use the logical analyzer, so I turned it on but I was surprised about the result. The scope was not able to decode the data or better to say it decodes it wrong. I was investigating it, downloaded the User Guide ( http://www.picotech.com/document/pdf/psw6.en-37.pdf ) and found a mismatch between the SW and description in Guide.

The break, PID & data bytes are decoded wrong. Only the Sync is decoded properly. So I went into advaced setting and tried to disable Invert Packet Bits. The decoding is now right except the Sync. :-)

When I compare the GUI interface of LIN in my PicoScope 6 and Guide, it is also different. Is there an update or its a matter of some settings or its a "bug"?

Have a nice day,
Vojtech
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Re: 4227 - LIN Logic Analysis

Postby Hitesh » Fri Oct 31, 2014 10:14 am

Hi Vojtech,

Please could you post a data file here or send it to support@picotech.com with your expected results.

I can then pass this on to the Development Team for investigation. The Serial Decoding feature has undergone review with some reworking identified following changes made for PicoScope 6.9.

With regards to the difference in the GUI, could you please indicate which page and provide screenshots please? I can notify the Technical Publications Team as required.

Thanks,
Hitesh

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Re: 4227 - LIN Logic Analysis

Postby Vojtech » Wed Nov 05, 2014 8:32 am

Hi Hitesh,

sorry for my late response, I was out of office without access to me equipment. Attached are two pictures captured during transmission of a LIN header from master and a response from Slave. The Sync Break is 13 bits long, the ID is 0x23 => PID is 0xA3. The response from Slave should be all zeros (by1 = 0x00, by2 = 0x00 .... by7 = 0x00). From the two pictures I've attached you can see the decoding of the whole LIN frame is wrong. By disabling the invert packet bits in settings, things which were decoded right are now wrong and vice versa. Also the break is decoded somehow curious.

Here is the link on PicoScope 6 guide I've used as a reference for the serial decoding. link to downloads: http://www.picotech.com/document/brochures.html?id=76

Guide in PDF:
http://www.picotech.com/document/pdf/psw6.en-37.pdf

Hope this helps,
Vojtech

PS: Let me know, if something is unclear or so. :-)
Attachments
PicoScope_LIN_InvertBits.png
LIN decoding with disabled Invert Packet Bits
PicoScope_LIN.png
LIN decoding with enabled Invert Packet Bits
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Re: 4227 - LIN Logic Analysis

Postby Hitesh » Thu Nov 06, 2014 5:39 pm

HIi Vojtech,

Could you please send the corresponding psdata file to support@picotech.com so that I can pass it on to the Development Team?

With regards to the PicoScope 6 manual, the link http://www.picotech.com/document/brochures.html?id=76 has a link to version 37 of the PicoScope 6 software. Is there another document that you have been referring to?

Thanks,
Hitesh

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Re: 4227 - LIN Logic Analysis

Postby Vojtech » Fri Nov 07, 2014 10:17 am

Hi Hitesh,

Don't understand, what you mean with psdata (does psdata = print screen data?). The pictures can be downloaded from the forum, but sure, I can send them to the email you gave me. In case its some PicoScope format, just let me know please, I'll aquire the data once more.

Regarding the manual, the first link points to place, where I found the PicoScope 6 User’s Guide. The second one is a link direcly to the PDF I was talking about. To be more precise, in the pdf, on page 194, chapter 9.6.6 LIN Protocol, the GUI differs in comparison to PicoScope 6 SW. Also the decoding of LIN in the User's Guide is performed properly in comparison to the SW. So it's a bit confusing.
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Re: 4227 - LIN Logic Analysis

Postby Hitesh » Fri Nov 07, 2014 12:45 pm

Hi Vojtech,

A psdata file is the PicoScope 6 file format.

Please click File -> Save As... in the PicoScope 6 software, select a file name and click 'Save'. I have responded to your support e-mail so you can send the file by reply.

Thanks,
Hitesh

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