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Issue with serial decoding

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Issue with serial decoding

Postby borkhuis » Tue Dec 09, 2014 9:29 am

Hello,

I am using PicoScope 6.10.6.1, with the PicoScope 2205 MSO. I am trying to capture I2C traffic. I have a number of frames that are separated by 20 ms up to 500 ms, containing 2 bytes per message

I would like to decode these messages, however, when looking at the resulting data I am missing quite a lot of message.

The messages that are separated by more than 200 ms are usually decoded correctly, but of the messages that are "close" together I am usually only seeing one.

I have tried using the short timebase (200 us/div). This will show one message in the capture screen, and decoded correctly. When I use the Accumulate option I see that a lot of messages are missed. So it looks like that after the data is captured the processing takes a lot of time to decode and does not capture during this period.

I also tried using a long timebase (500 ms/div). Now I see a lot of messages in the capture screen, but when looking at the serial data only some of the messages are not decoded, or multiple messages are combined into one (I saw at one occasion that 4 messages were combined into one address byte).

Is there a way to make the serial decode work better of faster, or do I have to change some settings to enable the serial decoding? Can I also capture and later do the serial decode, after all the data over a long period has been captured?

Regards,
Johan Borkhuis
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Re: Issue with serial decoding

Postby Hitesh » Tue Dec 16, 2014 11:24 am

Hello Johan,

It might be that the time to process the data is causing the messages to be missed between captures.

Are you using a trigger at all on the signal?

It is possible to apply serial decoding post capture so that might be worth trying.

If you are still experiencing issues, please post an example psdata file here or e-mail it to support@picotech.com and we can investigate further.

Regards,
Hitesh

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Re: Issue with serial decoding

Postby borkhuis » Tue Dec 16, 2014 1:11 pm

Hitesh,

Thank you for your answer. We managed to improve the processing by optimizing buffer and capture speed. However, we were still missing data between buffers.

Where can I find information on post-capture serial decoding? That would sound like something that could be even better. I don't mind that I have to process the data afterwards, as long as it is possible to view all data.

Regards,
Johan Borkhuis
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Re: Issue with serial decoding

Postby Hitesh » Tue Dec 16, 2014 5:41 pm

Hi Johan,

The best thing is to capture the data without any Serial Decoding options set, then after capturing the data, click Tools -> Serial Decoding and set up the serial decoding parameters as desired.

PicoScope 6 should then decode the data.

Regards,
Hitesh

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