About issue CMD19 and response R1 in SDR104 mode in i.MX6DQ.

[keitanagashima]

Dear All,

Hello. I have two questions about CMD19 (i.MX6) and response (SD card) in SDR104 mode.

We had measured the 2 pattern waveform.

Refer to attached file and please answer to my questions.

Best Regards,

Keita

[igorpadykov · Accepted solution]

Hi Keita

>[Question 1] The waveform looks two different Pattern (1 and 2) about CMD19 issue.

>Is this phenomenon normal?

Such behaviour can be caused by signal integrity issues (noise, poor signal)

so both processor and card can not receive data properly and processor retries

many times to send data.

This can not be considered normal, as with good signal processor and card

will get data properly and will not retry.

>[Question 2] The waveform looks i.MX6 couldn't read R1 correctly.

Yes you are right.

>Can this phenomenon happen like a missing to read CMD regularly?

Yes.

Best regards

igor

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