PMIC_ON_REQ Behaviour

[krishnaprasada]

Hi

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 :

1. Can the system come up automatically second time without pressing ON_OFF Button again?
2. What are the criteria’s to assert “PMIC_ON_REQ”?
3. Whether the PMIC_ON_REQ gets asserted/de-asserted only by ON_OFF Button press?
4. 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?
5. Once SOC is powered up, will it change the state of  PMIC_ON_REQ from Low to High?

Please clarify,

Sincerely

[YixingKong]

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

[YixingKong]

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

[JorgeRama_rezRi]

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

Best regards.

Jorge.

[JorgeRama_rezRi]

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.

[VladanJovanovic]

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.