Which reset switch wiring is best to do i.MX6 POR every time?

[torus1000]

Hi,

I compared circuit diagrams between MX6Q,MX6SL and MX6SX-SDB then found  STM6779YWB6F added to the PMIC_PWRON line.
Please see attached. According to the Note ii*, the purpose of this modification is as following.

*Note ii
Delay the PMIC_PWRON >500ms for the
1st-time power-on (VSNVS_3V0 is first applied),
to ensure 32.768kHz xtal osc output is stable.

So I just want to know the importance of this modification.

- Is the scope of this Note for the i.MX6SX only? Or all MX6-SDB should add STM6779YWB6F?
- Is it mandatory or is it OK to leave it if I don't care when my first manual reset ignored?
- Which reset switch wiring is best to do POR every time? (see below)

Can anyone help me?

Thanks.

[Yuri · Accepted solution]

Hello,

Using voltage supervisor for POR is not mandatory for i.MX6

(it is just enough to follow recommended in the Datasheets
power up sequence), but it is good design style, which allows
to get stable POR signal, that may be prolonged as needed.
The only negative feature here is price increasing.

I would recommend the solution of AN5161 for all i.MX6(s).

Have a great day,
Yuri

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