RT685 duty cycle changes during I3C communication

[melanie]

Hi @kerryzhou 

according to the frequency configuration shown in below picture. the duty should be 50%. push-pull hign is 40ns  push pull low is also 40ns.

but I find the actual duty cycle is not  always 50% in push-pull mode, somrtimes it is 75%. you could check the below timing capture.push-pull hign is 60ns  push pull low is also 20ns.

could you please explain this duty cycle changing phenomenon? Thanks

Best Regards,

Melanie 

[kerryzhou]

Hi @melanie ,

  Thank you for your interest in the NXP MIMXRT product, I would like to provide service for you.

   From your test result picture, it is from the logic analyzer, please also use the Oscilloscope  to test the I3C wave, whether still find the duty change issues? As in the logic analyzer, some interference in the signal bus may also influence the test result, then, oscilloscope will be the true result.

   Please check it again with oscilloscope, thanks.

   If you still have issues about it, please kindly let me know.

Best Regards,

Kerry

[melanie · Accepted solution]

HI Kerry,

Thanks for your suggestion.

It is difficult to capture timing sequence by Oscilloscope.