Serial Decoding - SPI support

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holgh
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Serial Decoding - SPI support

Post by holgh » Wed Jun 20, 2012 8:37 am

Hello community,

I am using Picoscope 2205 MSO, trying to decode serial SPI data on digital input channels (D0: clock, D1: SS, D2 MOSI).
Clock polarity (CPOL) is set to 0, with clock phase (CPHA) set to 1.

I can't find a setting for clock phase ... and the with the settings provided I cannot decode my signals correctly.

What can I do?

Thx for help!

Martyn
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Re: Serial Decoding - SPI support

Post by Martyn » Wed Jun 20, 2012 9:14 am

Can you go to "File->SaveCurrentWaveform" to save a psdata file which you can post here for us to take a look at.
Martyn
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holgh
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Re: Serial Decoding - SPI support

Post by holgh » Wed Jun 20, 2012 11:30 am

Here you have ...

Thx!
Attachments
20120620-SPI-Log.psdata
SPI data log (PicoScope V6.7.2.1 Beta)
(15.71 KiB) Downloaded 235 times

Martyn
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Re: Serial Decoding - SPI support

Post by Martyn » Thu Jun 21, 2012 8:05 am

You are correctly set up for clock polarity zero and phase of 1 by sampling clock on falling edge.

I would suggest triggering on a digital channel, not Chan A, and looking at your data I would suggest rising edge on D1 with no pre trigger which will leave you with a clean trace before you start decoding. I think the decode routine is being confused by the data at the start of the window.

Do you know what data you are expecting to decode ?
Martyn
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holgh
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Re: Serial Decoding - SPI support

Post by holgh » Thu Jun 21, 2012 12:21 pm

Thx for your hint.

Basically it's a good idea, except that the last byte is not recognized (see attachment).
But, in fact, I need to see SPI data at a certain time triggered on analog channel A, of couse ;-).

SPI Data input should not be too difficult to decode, so I hope to arouse some ambition in your team. And, btw, it would ebe nice if the code is more robust towards noise spikes in the digital domain.

Thx,
Holger
Attachments
21120620-SPI-Log.psdata
triggered on chip select line
(12.34 KiB) Downloaded 209 times

Martyn
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Re: Serial Decoding - SPI support

Post by Martyn » Fri Jun 22, 2012 9:44 am

It makes perfect sense to me so I have put in a feature request to enable serial decoding from a vertical cursor.
Martyn
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holgh
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Re: Serial Decoding - SPI support

Post by holgh » Fri Jun 22, 2012 3:49 pm

Thx Martyn!

MSO Fan
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Re: Serial Decoding - SPI support

Post by MSO Fan » Fri May 10, 2013 6:22 am

It makes perfect sense to me so I have put in a feature request to enable serial decoding from a vertical cursor.

- just checking to see if this feature/enhancement has been implemented? Thx

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Re: Serial Decoding - SPI support

Post by Martyn » Mon May 20, 2013 11:04 am

It didn't make it into the 6.7 release, but may catch the 6.8 Beta which will be including some new serial decoding features.
Martyn
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