i.MX8QM PMIC_ON_REQ control

[peter_pinewski]

Customer: John Deere

Device:  mx8qm

‌

Hi,

John Deere is wondering what all can cause the PMIC_ON_REQ line of the mx8qm to go high.  They can force it low through the SCFW by calling SNVS_PowerOff() but they cannot find a way to set it back high.

They have multiple inputs that can turn on the PMIC power and they have these OR'd together.  The problem is that these other inputs can turn on the PMIC power but they see that the PMIC_ON_REQ stays low.  They need this to come high when they start up. 

Is there a way to control this pin directly with the mx8?

what can all drive this pin low?

what can drive this pin high?

Thanks,

Peter

[igorpadykov · Accepted solution]

Hi Peter

formally setting PMIC_ON_REQ can be done with SCFW APIs

described in SCFW Porting Kit documentation, like:

sc_pm_set_sys_power_mode(ipc, SC_PM_PW_MODE_OFF),

sc_pm_set_sys_power_mode(ipc, SC_PM_PW_MODE_ON),

But last call is sensless (for that reason there is only SNVS_PowerOff() provided)

since assumed that in that state board is powered off (PMIC in off state) and SCFW

APIs can not run on unpowered processor.

Only way to set PMIC_ON_REQ when processor is unpowered is to use ONOFF signal

or RTC wake-up: rtcwakeup.c\mxc_rtc\test - imx-test - i.MX Driver Test Application Software 

Best regards
igor
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[peter_pinewski]

Thanks igor.

This was also confirmed in another post that i was monitoring that states the PMIC_ON_REQ is controlled only by HW.

https://community.nxp.com/message/1287450?commentID=1287450&et=notification.mention#comment-1287450

So, for the following scenario, I need a way to get the PMIC_ON_REQ back high.

Scenario:

- shut off the system with SNVS_PowerOff()  - this causes PMIC_ON_REQ to go low.

- PMIC/System power is turned on with external request  (i.e. ignition - not ONOFF or RTC)  - in this case, PWRON goes high because of external OR gate but PMIC_ON_REQ stays low.

- way to get PMIC_ON_REQ = 1 while powered?   Use RTC request as described in the post below:

URGENT! Wakeup from SNVS Mode using the RTC or Wakeup pins in i.MX8 

Thanks,

Peter