PN7462 wakes up from sleep mode with boot reason "E_SOFT_RESET"

[jayesh_joshi]

I am trying to implement a low power mode in my system in PN7462. 

PN7462 correctly goes into low power mode but it wakes up instantly with boot reason

" /** \b 0x0A */ E_SOFT_RESET, /**< Boot due to soft reset */"

After some further debugging I found that PN7462 wakes due to the "phhalPmu_PvddLdoStop();" API I am calling before entering low power mode. It is a must to turn off PVDD LDO for saving power in my system. If I remove the phhalPmu_PvddLdoStop line then the system works as expected.

I am attaching a code snippet for the same.

Please help me to enter sleep power mode with PVDD LDO turned off.

[jayesh_joshi]

@Kan_Li 

Yes there was issue with device not going into sleep mode and it was restarting afterwords. That is why boot reason was soft reset.

[Kan_Li]

Hello @jayesh_joshi ，

What about the wake up resources in your test? Is it some module powered by PVDD_LDO? Please kindly clarify.

Have a great day,
Kan

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[jayesh_joshi]

Hi Kan,

Thanks for the response,

Yes, we have an accelerometer which is powered by PVDD. And its interrupt is configured as a wakeup source. But if due to that if the device is waking up I thought the wakeup reason should be GPIO_INT. 

[Kan_Li · Accepted solution]

Hi @jayesh_joshi ,

Thanks for the information! I am confused about the accelerometer which is powered by PVDD, since you use it as a wake up resource which triggers a pulse to some GPIO of PN7462, how could it work without PVDD in the low power mode? I am also suspecting if the accelerometer pulled low the GPIO when PVDD is off so that it prevents PN7462 enter low power mode in this case. Please kindly check it on your side.

Hope that helps,

Have a great day,
Kan

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[jayesh_joshi]

Hi Kan

 " I am also suspecting if the accelerometer pulled low the GPIO when PVDD is off so that it prevents PN7462 enter low power mode in this case"

Kan in this case PN7462 won't restart but low power mode API will exit with a prevention error. Which is not happening here. Also in normal mode, I have checked accelerometer works without PVDD. I am keeping the I2C module running in low power mode may be due to the accelerometer is running.

[Kan_Li]

Hello @jayesh_joshi ,

Is it possible to share some code snippet regarding low power mode configuration on your board? We may try to reproduce this issue here.

Thanks for your patience!

Have a great day,
Kan

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