Test and Measurement Forum

Issue decoding i2c protocol

Forum for discussing PicoScope version 6 (non-automotive version)

Issue decoding i2c protocol

Postby vbr » Thu Feb 19, 2015 9:06 am

Hi all,

I experience some issues debugging embedded i2c frames. As you can see on the image attached, the frame looks good but i can't figure out why it's not decoded. I tried all configurations, i'm out of ideas.

Thanks for your help,
Attachments
i2c-conf.png
vbr
Newbie
 
Posts: 0
Joined: Thu Feb 19, 2015 8:38 am

Re: Issue decoding i2c protocol

Postby greg » Thu Feb 19, 2015 11:02 am

Hi vbr,

From the screenshot you have posted, it looks like the thresholds could be set too high.
It appears that you have 0 to 3.3v signals, so please try:

Threshold 1: 1v
Threshold 2: 2v
greg
PICO STAFF
PICO STAFF
 
Posts: 23
Joined: Mon Dec 16, 2013 9:09 am

Re: Issue decoding i2c protocol

Postby vbr » Thu Feb 19, 2015 12:52 pm

Thank you for this answer greg,

It worked perfectly, I actually used "Auto setup" to set tresholds and it looked like accurate values for me. What is difference between Treshold1 & Treshold2 ? Does it match for rising and falling edges ? The picoscope 6 user guide isn't explaining this (screenshots still from an older version).
vbr
Newbie
 
Posts: 0
Joined: Thu Feb 19, 2015 8:38 am

Re: Issue decoding i2c protocol

Postby greg » Mon Feb 23, 2015 9:55 am

Glad you have it working. Threshold 1 is a lower threshold and Threshold 2 an upper threshold for determining the signal edges. Providing two thresholds allows some hysteresis, and therefore the detection is more robust to signal noise.
greg
PICO STAFF
PICO STAFF
 
Posts: 23
Joined: Mon Dec 16, 2013 9:09 am

Re: Issue decoding i2c protocol

Postby vbr » Mon Feb 23, 2015 10:14 am

Ok, thank you for your help !
vbr
Newbie
 
Posts: 0
Joined: Thu Feb 19, 2015 8:38 am


Return to PicoScope 6 for Windows

Who is online

Users browsing this forum: No registered users and 0 guests