BG77 PSM - PWRKEY timing

Hi everyone,

I have a question regarding PSM on BG77 module. In the datasheet it says it is enough to drive PWRKEY low will wake up the module from PSM, could anyone confirm that before I send the device for the production?

How long should the key be pressed down for? For power up it is 500–1000 ms, for power down it is 650–1500 ms.

Thank you!

please refer to the picture

Hi @herbert.pan-Q,

I know what is the PWRKEY and how it works + also the schematic. What I need to know is, if PWRKEY can also be used for waking up the module from PSM and if so, what is the timing.

I am asking, because I would like to save one GPIO on MCU (no need to connect PON_TRIG).

Thank you!

PON_TRIG is recommended for PSM wake-up

Hi @herbert.pan-Q,

I know this as well. Please read my question once again, if PWRKEY can be used to wake up the module from PSM. And if so, how long should the PWRKEY be pulled down.

Thank you.

WRKEY may not enable PSM wakeup, so PON_TRIG is recommended

Could you please explain to me what do you mean by may not? Does it mean it works in some cases and in some not? Are there any conditions under which it will work every time when using PWRKEY?

Thank you.

No, I mean not supported, where do you know PWRKEY can trigger PSM wake up?

It is written in the Quectel datasheet.

Why PON_TRIG is not used?Is there any particular reason?

Hi @herbert.pan-Q,

I can not use PON_TRIG because I dont have any other free control pin on MCU. I thought I can use PWRKEY, as mentioned in the datasheet.

I have confirmed that 500-1000ms is required to be consistent with power on

So does it mean that PWRKEY can be used to wakeup the module from PSM? With the same timing as for regular power on?

yes,Please verify and test