Proper way to enter lowest power consumption for a LPN (Low Power Mesh Node) using System ON and RTC/GPIO wakeup.

[Jesper W.]

I'm converting an already working LPN that went into SystemOFF with GPIO wakeup for lowest power consumption.

Now I want to use the RTC2 as a secondary wakeup.

I know that i have to use the SystemON sleep mode and that the RAM is always retained in this mode.

1) So, What is the proper way to for the mesh/softdevice to enter/exit sleep mode, with lowest possible power consumption, and still keeping the friend "connection" to a friend-node ?
    Can I disable or pause the sd / mesh ? It seem like it is only possible to start the mesh, but not stop/pause it !!

2) Is it correct understood that the nordic mesh-protocol for a LPN, does not stores any infomation about established friend connection, that can be automatically restored after a Reset (power cycle) ?

3) When a LPN receives a friend offer (unicast-address), is it then possible to stores this address and later on reestablish a friend connection to the same unicast-address without loosing pending messages on the remote friend node ? 

[Mttrinh]

Hi,

1. Use LPN functionality as it is. After the friendship is established, it puts the device in sleep mode in between the polling intervals. See the LPN functionality's documentation.

2. Yes, it is according to the Mesh Profile Specification. The behavior of the LPN after power cycle is undefined. Since power cycle resets everything in the mesh stack, consequently LPN looses friendship.

3. No. Once the friendship is broken, or re-established with the same node, all previous messages are automatically cleared by the Friend node. This is as per the Mesh Specification