i.MX ProcessorsのトピックRe: PMIC_ON_REQ Behaviour

PMIC_ON_REQ Behaviour

krishnaprasada — Mon, 28 Oct 2013 19:11:00 GMT

I am designing a system with i.MX6 Dualite processor and external DC/DC Converters ( No PMU).

My system needs the Processor to turn ON automatically when the power is applied ( No Button press).

However I should be able to turn – off the processor via the switch connected to ON_OFF Button.

The system will be OFF for a specific duration and should turn ON again automatically..

Note that VDD_SNVS is always present.

I am making use of PMIC_ON REQ Signal along with a 555 timer to meet this requirement.

However my question is :

Can the system come up automatically second time without pressing ON_OFF Button again?
What are the criteria’s to assert “PMIC_ON_REQ”?
Whether the PMIC_ON_REQ gets asserted/de-asserted only by ON_OFF Button press?
Consider I turned off the unit by pressing ON_OFF Button. PMIC_ON_REQ = Low. When the system turns ON again automatically, Can it over drive PMIC_IN_REQ to High State from low state?
Once SOC is powered up, will it change the state of PMIC_ON_REQ from Low to High?

Please clarify,

Sincerely

Re: PMIC_ON_REQ Behaviour

VladanJovanovic — Fri, 01 Nov 2013 06:41:50 GMT

Table 60-3, Power Mode Transitions, in i.MX 6Dual/Quad Reference Manual gives some good info about this.

And for i.MX 6DualLite, it's Table 59-1 in DualLite/Solo ref. manual.

Re: PMIC_ON_REQ Behaviour

JorgeRama_rezRi — Mon, 04 Nov 2013 21:09:16 GMT

Hi,

1. Yes. As long as the processor start-up sequence is followed, the voltage levels are met and the POR_B signal is released after the power up sequence has finished, the processor will turn on.
2. PMIC_ON_REQ is a processor signal that turrns on the PMIC, but it actually doesn't affect the processor turn-on. The signal you should be looking at is POR_B. As I mentined, it must be asserted right after the power-up sequence finishes. You will need to control it with a voltage level equal to VDD_SNVS_IN, since this is the reference voltage of POR_B.

3. Yes, PMIC_ON_REQ is asserted with an ONOFF button press.

4. Not sure I understand this question. If the info above is not enough and you still need an answer on this, could you please elaborate?

5. PMIC_ON_REQ signal will stay high as long as the processor is on, and will go low when the system requires to turn off or go to sleep.

Best regards.

Jorge.

Re: PMIC_ON_REQ Behaviour

JorgeRama_rezRi — Mon, 04 Nov 2013 21:16:21 GMT

More useful info about PMIC_ON_REQ: https://community.freescale.com/docs/DOC-97660?et=watches.email.document

Best regards.

Jorge.

Re: PMIC_ON_REQ Behaviour

YixingKong — Fri, 21 Feb 2014 09:11:31 GMT

Hi,

Had your issue got resolved? If yes, we are going to close the discussion in 3 days. If you still need help, please feel

free to reply with an update to this discussion.

Thanks,
Yixing

Re: PMIC_ON_REQ Behaviour

YixingKong — Thu, 27 Feb 2014 03:36:50 GMT

Hi,

This discussion is closed since no activity. If you still need help, please feel free to reply with an update to this discussion, or create another discussion.

Thanks,

Yixing