Introduction

The Zigbee Sleepy-to-Sleepy (S2S) feature is the implementation of the IEEE 15.4 unsynchronized Coordinated Sample Listening (CSL) feature, as defined in the IEEE 802.15.4-2015 specification. Using two sleepy end devices, this feature allows one device to transmit using a preceding wake-up frame sequence, and a receiver to act on the wake-up frames to receive a final, coordinated payload

The following image demonstrates how an unsynchronized CSL transmission works with wake-up frames

startup

Some important points

  • S2S devices are not certifiable as Zigbee devices
  • A S2S receiver cannot be woken-up by a standart Zigbee packet
  • S2S network can use same parameters as a nearby Zigbee network (ext-pan-id, panid, network key, channel)
  • A S2S command using wake-up frame can be received by a standart Zigbee router when same network parameters are used
  • When a S2S receiver receives a S2S command, it reboroadcasts this command using standart Zigbee format (No wake-up frame)
  • No meshing is done on S2S network.
  • Any ZCL packet sent by a S2S initiator will use a wake-up frame (group, on-off, etc)

Sometimes a S2S receiver needs to receive commands not only from a S2S transmitter but also from an nearby Zigbee network. Multi-network feature of our Zigbee stack is a way to achieve this requirement. In this tutorial, we are going to cover this need.

Prerequisites

A s37 file for BRD4194A implementing multi-network functionnality is available here. Don't forget to flash a bootloader.

What you need

  1. SiSDK 2025.6.0 or newer installed on your machine.

  2. Sleepy2Sleepy package associated to the SiSDK version used. This is an on-demand package. You need to ask SiliconLabs support to get this package.

Setup of S2S package

Once SiSDK 2025.6.0 or newer is installed on your machine

  1. Close Simplicity Studio

  2. Unzip the S2S package. It should contain a protocol folder. Copy this folder to the SiSDK folder. You will be asked if you want to overwrite existing file in SDK, select "Yes".

startup

  1. Restart SimplicityStudio