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Controlling SNVS mode for i.MX8M

Question asked by Yannick B on Jun 4, 2020
Latest reply on Jun 8, 2020 by igorpadykov

Hi,

 

Current we're using an imx8m processor. I'd like to be able to make the processor sleep from a button, particularly the "SNVS/RTC mode" where almost everything is turned off. The PMIC used is the PF4210.

 

I have a few questions

 

1- I can't find any reference to the "SNVS mode" in the reference manual of the imx8 (IMX8MDQLQRM.pdf). Why is that? Page 977/6407 seems to show a flow diagram of the power modes. I see "SRTC", is that the same as the SNVS mode?

 

2- On the hardware level, how would it be possible to transition from the "ON" state to the "SNVS mode", which pins are involved, and how to trigger it (i.e. do we send a pulse of x seconds to a specific pin, we set something to zero, or...?)

Or is the SNVS mode activated from software only?

 

3- Is it possible to switch to the SNVS mode from software instead of from hardware (i.e. not from a physical button). Is there some documentation about it (I can't really find much).

 

4- Is there a PIN somewhere on the imx8 that can be used (an output) to determine if the imx8 is in the on state (i.e. is powered on, not sleeping nor being off).

 

5- If a GPIO is maintained constantly at a logic 1 for example, will it stay at logic 1 in SNVS mode or not? And when the processor exits SNVS mode (ON state), is the GPIO back on logic 1?

 

Thanks!

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