i.MX ProcessorsのトピックCorrect function about PMIC_STBY_REQ signal on Power-Up sequence.

Correct function about PMIC_STBY_REQ signal on Power-Up sequence.

t-iishii — Mon, 24 Oct 2016 01:34:33 GMT

Dear Team,

My customer ask me about PMIC_STBY_REQ signal between VSNVS power-up and POR_B to Hi.

It have some QA in Community but answer have 2 type.

One is a keep L signal is correct and must check power-up sequence.

Other is a undefined state so signal can not fixed to L or H.

Signal on our customer board, go to H after VSNVS on and return L before POR_B to H.

Does It have some problem on customer board and it must fixed?

or It is correct because signal state is undefined.

Which is correct answer?

Best regards,

Ishii.

Re: Correct function about PMIC_STBY_REQ signal on Power-Up sequence.

Yuri — Mon, 24 Oct 2016 03:53:02 GMT

Hello,

Generally it is assumed, that i.MX6 has always present power supply VDD_SNVS_IN.
But when this voltage is just applied, during its rising, ONOFF is considered as LOW, providing
PMIC power on activity. Strictly speaking, during (total) power up sequence i.MX6 pins state is
not pre-defined.

Have a great day,
Yuri

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

Re: Correct function about PMIC_STBY_REQ signal on Power-Up sequence.

t-iishii — Mon, 24 Oct 2016 10:21:47 GMT

Hi Yuri,

Thank you for your quick reply.

I will inform my customer based on your answer.

Best regards,

Ishii.