Auto wake up on RF activity in observer mode

[sunil.dhaduk]

Hi,

Is nRF51822 supporting any auto wake up functionality if there is any kind of activity on RF during observer mode?

[Susheel Nuguru]

Are you talking about BLE activity or any RF activity? With BLE, the softdevice will make sure that the chip wakes up from sleep during the RADIO traffic. Please be more descriptive about what you are actually looking for.

[sunil.dhaduk]

Hi Aryan,

I am talking about BLE activity over the air.

Is auto wake up is possible? If yes then which softdevice is supporting it?

[Susheel Nuguru]

You can use the radio notification mechanism from the SD which uses SWI1 IRQ. Tutorials for this can be found here

Softdevice documentation for this can be found here

[sunil.dhaduk]

Hi Aryan,

Thanks for your suggestion...

If observer receive any broadcaster packet from the air over 2.45GHz RF during its idle condition, will softdevice generate any soft interrupt to wake up?

[Susheel Nuguru]

If the observer is receiving any packets that means that the device is already active while the RADIO is on. And the chip is woken up by softdevice RTC0 interrupt. This is not in application control.

What happens is application start scanner and goes to sleep

Observer event is started by chip waking up by executing RTC0 handler code inside softdevice.

The packet is received and then the softdevice schedules future events and relinguishes control.

Application gain control and most probably looping to put chip to sleep like below

for (;;) { power_manage(); }

but if radio notification is enabled, then softdevice aprt from doing it normal work, will also trigger SWI1 interrupt which your application can listen to. And this is how your application can tell that RADIO event has happened.