Wi-Fi 6 + BLE (WiSeConnect 3) SDK Version 3.5.0 (June 18 2025) - Release Notes#

Simplicity SDK Version 2025.6.0

The WiSeConnect 3 SDK is the next-generation Wi-Fi 6 + BLE SDK for Silicon Labs customers, replacing WiSeConnect 2 with a modular design and organization of features into configurable components.

Click here for earlier releases.

Release Summary#

Release Item Version Release Date Release Notes Key Features API Changes Bug Fixes Chip Enablement

Wi-Fi

3.5.0

June 18, 2025

Release Notes

  • Auto Join support
  • AT Commands support
  • Wireless Query APIs modified to support fetching more details
  • Thread priority macros for Event and Command Engine threads
  • Fixes for Wi-Fi connection issues
  • Fixes in Wi-Fi scan for performance and accuracy
 None

Network Stack

3.5.0

June 18, 2025

Release Notes

  • Dual network stack support
  • DTLS client socket support
  • mDNS over IPv6 support
  • Support for socket bind before Wi-Fi connection
 None
  • Stability fixes for TLS sockets and VLAN
  • Fix for IP configuration failure
 None

SiWx91x Bluetooth LE

3.5.0

June 18, 2025

Release Notes

Support for concurrent 8 BLE peripherals + 2 BLE central devices None
  • Stability fixes for BLE connections
  • Power optimizations
  • Functional fixes for regulatory compliance
  • Functional fixes for RSSI accuracy
 None

Multiprotocol

3.5.0

June 18, 2025

Release Notes

  • Support for concurrent 8 BLE peripherals + 2 BLE central devices + WLAN MQTT data transfer
  • Support for concurrent 2 BLE connections with advertising extensions + WLAN TCP TX data transfer
 None
  • Stability fixes for BLE scanning and advertising + WLAN connections
  • Stability fixes for Matter commissioning with Wi-Fi + BLE
 None

SiWx91x Platform

3.5.0

June 18, 2025

Release Notes

  • Driver support for BOD, GPDMA, HSPI Secondary, and OPAMP peripherals
  • Additional driver features for existing peripherals
  • Sleep stability improvements
  • APIs for newly introduced peripherals
  • Low-power GPIO interrupt API changes with deprecation
  • Stability and functional fixes for DMA, QEI, SSI, and RHT sensors
  • Configuration fixes for PSRAM, ULP I2S, and PWM
 None

Impact of Release Changes#

Impact Statements | Migration Guide

Impact Statements#

Change Impact Affected Software Variants if applicable Affected Modes Affected OPNs / Boards / OPN Combinations Affected Host Interfaces

Deprecation of Watchdog Timer peripheral

Need to update existing applications to use the Watchdog Manager service instead.

Standard and Lite

SoC
  • OPNs: All
  • Boards: All

N/A

Several APIs deprecated

See the Migration Guide section for details of changes needed in existing applications.

Standard and Lite
  • SoC
  • NCP
  • OPNs: All
  • Boards: All

UART, SPI

Migration Guide#

Click here for the migration guide for deprecated, removed, and modified items.

Using This Release#

What's in the Release? | Compatible Software | Installation and Use | Help and Feedback

What's in the Release?#

Compatible Software#

Software Compatible Version or Variant
Connectivity Firmware

Note: The firmware above is used by the network processor on SiWx91x parts.

Simplicity SDK

2025.6.0

Note: The WiSeConnect Simplicity Studio extension automatically pulls in the compatible Simplicity SDK version. See the Getting Started Guides for more details.

Simplicity Studio

5.11.0

Note: To install Simplicity Studio, see the Install Simplicity Studio section.

RTOS

FreeRTOS v11.1.0

Note: The WiSeConnect Simplicity Studio extension automatically pulls in the compatible FreeRTOS version. See the Getting Started Guides for more details.

Toolchains in Simplicity Studio

GNU ARM v12.2.1

Note: To install the above toolchain, see the Install the GNU ARM v12.2.1 Toolchain section.

Installation and Use#

Note:

  • To upgrade an earlier version of board BRD4338A (standalone or included in pro kit Si917-6031A), see the SiWG917 - TA Flash Memory Map Change Guide.

  • The release packages will include bug fixes, enhancements, and new features for both 'SDK' and 'Firmware'. Customers should update and use the 'SDK' and 'Firmware' from the same release package. Combinations of SDK and Firmware that are not released together are not supported.

  • It is mandatory to perform an over-the-air (OTA) firmware update using a combined image (network processor (NWP) and application processor (M4) in a single image), when upgrading from any previous version to version 3.5.0. Updating the NWP image and M4 image one after the other should be avoided as it may result in undefined behavior due to version mismatch.

To run your first demo with the Simplicity Studio integrated development environment (IDE), see our Getting Started Guides.

To kick start your development and debugging with the Simplicity Studio IDE, see our Developer's Guide.

To learn about flashing binaries, security key management, and calibration of crystal and GAIN offsets with Simplicity Commander, see the SiWx917 SoC Manufacturing Utility User Guide.

To learn about Advanced Energy Monitoring (AEM) to measure ultra-low power capability on development boards (radio boards or dev kit boards or explorer boards), see the Measure Power Usage section.

To learn about the Pin Tool for pin configurations on development boards, see the Pin Tool user guide for Simplicity Studio.

To review Security and Software Advisory notifications and manage your notification preferences:

  1. Go to https://community.silabs.com/.

  2. Log in with your account credentials.

  3. Click your profile icon in the upper-right corner of the page.

  4. Select Notifications from the dropdown menu.

  5. In the Notifications section, go to the My Product Notifications tab to review historical Security and Software Advisory notifications.

  6. To manage your preferences, use the Manage Notifications tab to customize which product updates and advisories you receive.

For recommended settings, configurations, and usage guidelines, see the Recommended Settings section.

To learn more about the software in this release, dive into our online documentation.

Help and Feedback#

Feature Matrix#

The following sections cover the features of the Wi-Fi 6 + BLE (WiSeConnect 3) SDK:

Supported Features#

Wi-Fi | Network Stack | SiWx91x Bluetooth LE | Multiprotocol | SiWx91x Platform

Note: The following list specifies the hardware parts compatible with the WiSeConnect 3 SDK:

Wi-Fi#

Operating Modes | Wi-Fi Protocol Features | Wi-Fi 6 Protocol Features | Wi-Fi Scan | Wi-Fi Station Mode | Access Point Mode | Wi-Fi Power Save

Operating Modes#
Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
Wi-Fi Station (STA)

Wi-Fi Station mode with 802.11ax and 802.11n support

 GA

API Reference Guide - Client
  • Firmware variants: Standard and Lite
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI

Wi-Fi - Station Ping
Wi-Fi Access Point (SoftAP)

Wi-Fi Access Point mode with 802.11n support

 GA

API Reference Guide - Access Point
  • Firmware variants: Standard only
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI

Wi-Fi - Access Point
Wi-Fi Station (STA) + Access Point (SoftAP)

Wi-Fi concurrent mode support over the same channel- Station with 802.11ax and 802.11n + Access Point with 802.11n

 GA
  • Firmware variants: Standard only
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI

Wi-Fi - Concurrent Mode
Wi-Fi Enterprise Client

Support for EAP-TLS, EAP-TTLS, EAP-FAST, and PEAP security.

 GA

API Reference Guide - Client
  • Firmware variants: Standard only
  • OPNs All
  • Boards All
  • Modes: NCP
  • Host interfaces: UART, SPI

Wi-Fi - Enterprise Client
Wi-Fi Transceiver

Wi-Fi Transceiver mode with 802.11b/g support

 GA

API Reference Guide - Wi-Fi Transceiver
  • Firmware variants: Standard only
  • OPNs All
  • Boards All
  • Modes: NCP
  • Host interfaces: UART, SPI

None
Wi-Fi Transmit Test Mode

Custom, connection-less testing in SoC or NCP mode

 GA
  • Firmware variants: Standard only
  • OPNs All
  • Boards All
  • Modes: NCP
  • Host interfaces: UART, SPI

Wi-Fi - WLAN RF Test
Wi-Fi Protocol Features#
Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
IEEE 802.11b/g/n (2.4 GHz)

IEEE 802.11b/g/n Wi-Fi standards supported over the 2.4 GHz band.

 Beta
  • Firmware variants: Standard and Lite
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI

Wi-Fi - Station Ping
IEEE 802.11ax (2.4 GHz)

IEEE 802.11ax Wi-Fi standard supported in the 2.4 GHz band.

 Beta

API Reference Guide - Client
  • Firmware variants: Standard and Lite
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI

Wi-Fi - Throughput
Wi-Fi Multimedia (WMM) Quality of Service (QoS)

Wi-Fi Multimedia (WMM) Quality of Service (QoS)

 GA

API Reference Guide - Client
  • Firmware variants: Standard and Lite
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI

Wi-Fi - Throughput
2.4 GHz Band

Supported channels:

  • 1-11 (US)
  • 1-13 (Europe)
  • 1-14 (Japan)
 GA
  • Firmware variants: Standard and Lite
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI
Wi-Fi Alliance (WFA) Certification

Pre-testing completed for WFA certification. One recently added test case is currently failing, and a fix will be included in an upcoming release. Despite this, the Wi-Fi SDK remains certifiable.

 GA

API Reference Guide - Client
  • Firmware variants: Standard only
  • OPNs All
  • Boards All
  • Modes: SoC only

None
Wi-Fi 6 Protocol Features#
Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
MU-MIMO (DL)

Enable a Wi-Fi station to receive data that is sent by the access point to multiple stations at the same time in the downlink direction, improving network efficiency.

 GA

API Reference Guide - Client
  • Firmware variants: Standard
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI

Wi-Fi - Throughput
OFDMA (UL/DL)

Enable a Wi-Fi station (STA) to simulateneously transmit data to other stations and receive data from other stations, by using assigned sub-channels (resource units) within a shared channel, enhancing efficiency in both uplink and downlink directions.

 GA

API Reference Guide - Client
  • Firmware variants: Standard and Lite
  • OPNs All
  • Boards All
  • Modes: SoC, NCP
  • Host interfaces: UART, SPI
  • Wi-Fi - Throughput
    		•
    Target Wake Time (TWT)

    iTWT, TWT I-frame & TWT enhancements (automatic TWT configuration)

    		 GA
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - TWT Use case demo app
    BSS Coloring

    Identify transmissions from different networks marked with unique color identifiers to reduce interference and improve performance in dense environments.

    		 GA

    sl_si91x_transmit_test_start
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wireless Test
    Multiple BSSID (MBSSID)

    Connect as a Wi-Fi station to multiple virtual networks (SSIDs) broadcast from a single Wi-Fi access point using a single physical radio, enabling efficient management of multiple wireless networks on the same hardware.

    		 GA

    API Reference Guide - Client
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Station Ping
    Wi-Fi Scan#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Selective Scan

    Channel specific scan

    		 GA

    API Reference Guide - Scanning
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Roaming
    Active / Passive Scan

    Active scanning to send probe requests to discover networks; and passive scanning to listen for beacon frames from access points.

    		 GA

    API Reference Guide - Scanning
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Roaming
    Background (BG) Scan

    Background scan in station mode

    		 GA

    API Reference Guide - Scanning
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Roaming
    Wi-Fi Station Mode#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Wi-Fi Re-join

    Enable a device to automatically re-connect to a previously connected wireless network after disconnection.

    		 Beta
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi Provisioning via Access Point
    Wi-Fi Roaming
    • Opportunistic Key Caching (OKC)
    • Pairwise Master Key (PMK) caching
    • Pre-authentication
    		 Alpha

    sl_wifi_set_roam_configuration
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Roaming
    BG Scan
    • Opportunistic Key Caching (OKC)
    • Pairwise Master Key (PMK) caching
    • Pre-authentication
    		 GA

    sl_wifi_set_roam_configuration
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Roaming
    Wi-Fi Security
    • Wi-Fi open security
    • WPA
    • WPA / WPA2 Mixed Mode
    • WPA2 Personal
    • WPA2 enhancements
    • WPA2 Enterprise security
      • Method: PEAP/TTLS/TLS 1.0/TLS 1.2/FAST/LEAP
    • WPA3 Personal
    • WPA3 Personal Transition Mode
    • WPA3 Enterprise security
      • Method: PEAP/TTLS/TLS 1.0/TLS 1.2/FAST
    • Known security vulnerabilities handled:
      • WPA2 KRACK attacks
      • Fragment and Forge
    		 Beta

    sl_wifi_connect
    • Firmware variants: Standard and Lite (Enterprise security not applicable for Lite)
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI
    Access Point Mode#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    4-client Support

    Allow up to 4 clients to connect to the access point.

    		 GA

    sl_wifi_init
    • Firmware variants: Standard only
    • OPNs All
    • Boards All
    • Modes: SoC only
    • Host Interfaces: N/A

    Wi-Fi - Access Point
    Hidden SSID Mode

    Prevent a Wi-Fi network’s SSID from being broadcast in beacon frames, making the network name invisible to casual scans.

    		 GA

    sl_wifi_init
    • Firmware variants: Standard only
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Access Point
    Auto Channel Selection

    Dynamically select the optimal Wi-Fi channel to minimize interference and improve network performance.

    		 GA

    sl_wifi_start_ap
    • Firmware variants: Standard only
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Access Point
    Scan in Access Point Mode

    Wi-Fi scanning in access point mode

    		 GA

    sl_wifi_start_scan
    • Firmware variants: Standard only
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi Provisioning via Access Point
    Wi-Fi Security
    • Wi-Fi open security
    • WPA2 Personal
    • WPA3 Personal
      • H2E Method only
    • WPA Mixed Mode (WPA/WPA2)
    		 GA

    sl_wifi_start_ap
    • Firmware variants: Standard only
    • OPNs All
    • Boards All
    • Modes: SoC only
    • Host Interfaces: N/A

    Wi-Fi - Access Point
    Wi-Fi Power Save#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Standby Associated

    Standby Associated (connected sleep) with Max/Enhanced Max/Fast Power Save Profile (PSP)

    		 GA

    API Reference Guide - Wi-Fi Power and Performance
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Power Save Standby Associated
    Network Processor (NWP) Deep Sleep

    Network Processor (NWP) Deep Sleep with and without RAM retention

    		 GA

    API Reference Guide - Wi-Fi Power and Performance
    • Firmware variants: Standard and Lite
    • OPNs All
    • Boards All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Power Save Deep Sleep

    Network Stack#

    Core Networking Features | Advanced Networking Features | IoT Cloud Integration

    Core Networking Features#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Core Network Protocols

    IPv4, UDP, TCP, ARP, ICMP, ICMPv6

    		GA
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI
    Internet Protocol version 6 (IPv6)

    Connect and exchange data with other hosts using the IPv6 protocol in the networking layer of the network stack.

    		 Beta
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI
    TLS Client

    Supported versions 1.0, 1.2, 1.3

    		 GA

    API Reference Guide - BSD Sockets
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - TLS Client
    DHCP Client

    Support for DHCPv4 and DHCPv6

    		 Beta

    sl_net_set_profile
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI
    TCP/IP Bypass (Hosted Network Stack)

    LwIP as hosted network stack for reference

    		 GA

    API Reference Guide - Network Management
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - LwIP TCP Client
    DHCP Server

    Support for DHCPv4 and DHCPv6

    		 GA

    sl_wifi_init
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Access Point
    BSD, ARM IoT, and SiWx91x Sockets

    BSD, ARM IoT, and SiWx91x Sockets

    		 GA
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Throughput
    Advanced Networking Features#

    Note: See DTLS Error Codes for a list of potential error codes encountered during a DTLS connection.

    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Advanced Network Protocols
    • HTTP/HTTPS Client
    • mDNS
    • DNS Client
    • Embedded MQTT
    • MQTT on host (AWS and Azure)
    		 GA
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI
    HTTP Server

    Host a Hyper-text Transfer Protocol (HTTP) or Hyper-text Transfer Protocol: Secure (HTTPS) server to host and serve HTTP content to HTTP clients.

    		Beta

    API Reference Guide - HTTP Server
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - HTTP Server

    mDNS over IPv6

    Host a Multicast Domain Name (mDNS) service over Internet Protocol version 6 (IPv6) to allow other network devices to look up your IPv6 address based on your host name.

    		Alpha

    API Reference Guide - mDNS
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    None

    SNTP Client

    Retrieve date and time information from an SNTP server.

    		 GA

    API Reference Guide - SNTP
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - SNTP Client
    IGMP

    Add the SiWx91x device to a multicast group and exchange multicast data on a UDP socket.

    		 GA

    sl_net_join_multicast_address
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    None
    IoT Cloud Integration#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    AWS IoT Core

    Configure SiWx91x as an IoT device and securely connect to the AWS IoT cloud to subscribe and publish on topics using the AWS MQTT library (version 3.1.0).

    		 GA

    None
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - AWS IoT MQTT Client
    Azure IoT

    Configure the SiWx91x as an Azure device endpoint, connect, and exchange messages with the Azure IoT Hub.

    		 Beta

    None
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - Azure IoT MQTT Client Application

    SiWx91x Bluetooth LE#

    Legacy Features | Advertising Extensions | Power Save

    Legacy Features#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    GAP with up to 2 connections
    • Advertising, scanning, initiation, connection, and bonding, with a maximum of 2 connections
    • Handling of access modes and procedures of the device including device discovery, link establishment, link termination, initiation of security features, and device configuration
    		 GA

    API Reference Guide - BLE
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART
    GAP with up to 10 connections
    • Advertising, scanning, initiation, connection, and bonding, with a maximum of 8 peripheral connections and 2 central connections
    • Handling of access modes and procedures of the device including device discovery, link establishment, link termination, initiation of security features, and device configuration
    		 Alpha

    API Reference Guide - BLE
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    Unified app for Bluetooth and Wi-Fi

    Generic Attribute Protocol (GATT)

    GATT defines how data is organized and exchanged between devices. It builds on the Attribute Protocol (ATT) by organizing data into hierarchical structures of profiles, services, and characteristics.

    		 GA

    API Reference Guide - BLE
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - Multiconnection Gatt Test
    Attribute Protocol (ATT)

    ATT is the fundamental layer responsible for managing data transmission and handling between devices, particularly within the context of the Generic Attribute Profile (GATT).

    		 GA

    API Reference Guide - BLE
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - Multiconnection Gatt Test
    Security

    The Security Manager (SM) defines the protocol and behavior to manage pairing, authentication, and encryption, using a key distribution approach to perform identity and encryption functionalities in radio communication.

    		 GA
    • rsi_ble_smp_pair_request
    • rsi_ble_smp_pair_failed
    • rsi_ble_ltk_req_reply
    • rsi_ble_smp_pair_response
    • rsi_ble_smp_passkey
    • rsi_ble_start_encryption
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI
    LL Privacy 1.2

    Allow devices to use temporary, non-identifiable addresses (Resolvable Private Addresses or RPAs) instead of their public identity address.

    		 GA
    • rsi_ble_resolvlist
    • rsi_ble_get_resolving_list_size
    • rsi_ble_set_addr_resolution_enable
    • rsi_ble_set_privacy_mode
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI

    BLE - Privacy
    Accept List

    Restrict the connections permitted to a BLE device.

    		 GA
    • rsi_ble_addto_acceptlist
    • rsi_ble_deletefrom_acceptlist
    • rsi_ble_clear_acceptlist
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI

    BLE - Privacy
    Directed Advertising

    Broadcasting information to a specific device (the scanner) identified by its address.

    		 GA

    rsi_ble_start_advertising
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI
    LE PHY and Coded PHY
    • LE PHY (1 Mbps, 2 Mbps, 2M PHY): Higher data throughput physical layer (2 Mbps) enabling faster data transfers while maintaining power efficiency for high-bandwidth applications.
    • Coded PHY (125kbps, 500kbps): Extended range capability utilizing Forward Error Correction (FEC) allowing connectivity at up to 4x the standard distance in open environments.
    		 GA
    • rsi_ble_readphy
    • rsi_ble_setphy
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI

    None
    LE Dual Role Topology

    Allow SiWx91x to function as both a central and a peripheral simultaneously on different connections.

    		 GA
    • rsi_ble_start_advertising
    • rsi_ble_start_scanning
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - Multiconnection Gatt Test
    LE Data Packet Length Extensions (DLE)

    Allow the SiWx91x device to transmit data packets with larger payloads, increasing the maximum data rate and potentially improving throughput.

    		 GA

    rsi_ble_set_wo_resp_notify_buf_info
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI

    BLE - Multiconnection Gatt Test
    Asymmetric PHYs

    Allow the use of different PHYs (Physical Layers) for transmission (TX) and reception (RX).

    		 GA

    rsi_ble_setphy
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI

    None
    LE Channel Selection Algorithm 2 (CSA#2)

    Algorithm used to determine the channel index for the next connection event, in order to improve channel hopping and minimize interference, especially in high-throughput and high-interference scenarios.

    		 GA

    None
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI

    None
    LE Secure Connections

    Use Elliptic-Curve Diffie-Hellman (ECDH) cryptography to generate a public-private key pair.

    		 GA
    • rsi_ble_smp_pair_request
    • rsi_ble_smp_pair_failed
    • rsi_ble_ltk_req_reply
    • rsi_ble_smp_pair_response
    • rsi_ble_smp_passkey
    • rsi_ble_start_encryption
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI

    BLE - Secure connections
    Advertising Extensions#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Extended Advertising

    Use secondary advertising channels to offload data that would otherwise be transmitted on the primary advertising channel. Enable multiple sets of advertisements, each with their own data, intervals, duration, address types, filter policies, and PHY rates.

    		 GA
    • rsi_ble_get_max_no_of_supp_adv_sets
    • rsi_ble_set_ae_params
    • rsi_ble_start_ae_advertising
    • rsi_ble_get_max_adv_data_len
    • rsi_ble_set_ae_set_random_address
    • rsi_ble_set_ae_data
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - Unified AE app
    Extended Advertising and Scanning
    • Extended Advertising: Enable the discovery of more data than the 31 bytes of traditional advertising by offloading data to an auxiliary advertising packet on a secondary channel.
    • Extended scanning: Enable scanning for different PHY rates and have a different set of scan interval, scan window, and scan type for each.
    		 GA
    • rsi_ble_ae_set_scan_params
    • rsi_ble_ae_set_scan_enable
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - Unified AE app
    Periodic Advertising

    Allow sending non-connectable advertisements at fixed intervals.

    		 GA
    • rsi_ble_app_set_periodic_ae_params
    • rsi_ble_app_set_periodic_ae_enable
    • Firmware variants: Standard and Lite
    • OPNs : All
    • Boards : All
    • Modes : SoC and NCP
    • Host interfaces : SPI,UART

    BLE - Unified AE app
    Periodic Advertising Scanning

    Scan for periodic advertisements.

    		 GA
    • rsi_ble_ae_set_scan_params
    • rsi_ble_ae_set_scan_enable
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - AE central
    Periodic Advertising List

    A schedule of when a device will send its advertisement data at regular intervals, allowing other devices to synchronize with the advertiser and receive the data at the specified times, saving power and improving efficiency.

    		 GA
    • rsi_ble_ae_dev_to_periodic_list
    • rsi_ble_ae_read_periodic_adv_list_size
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - AE central
    LE Periodic Advertising Synchronization

    Allow multiple devices to wake up and receive data from a single source at the same time, enabling energy-efficient communication and data sharing.

    		 GA

    rsi_ble_ae_set_periodic_sync
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - AE central
    Simultaneous Scanning on 1 Mbps and Coded PHY

    Listening for advertisements on both PHYs at the same time.

    		 GA
    • rsi_ble_ae_set_scan_params
    • rsi_ble_ae_set_scan_enable
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - Unified AE app
    Power Save#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Wireless Power Save
    • BLE Advertising with power save
    • BLE Scan with power save
    • BLE connection with power save
    • Only Max PSP power save mode is supported in BLE
    		 GA
    • rsi_bt_power_save_profile
    • sl_wifi_set_performance_profile_v2
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    BLE - Powersave

    Multiprotocol#

    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Wi-Fi Station (STA) + BLE Mode

    Co-existence of Wi-Fi Station (STA) mode and Bluetooth Low Energy (BLE) on the same radio, supporting complex use cases with minimal interference. This solution is built on a Time Division Multiplexing (TDM) architecture that schedules radio access between Wi-Fi and BLE with optimal performance.

    		 Alpha
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI
    Wi-Fi + BLE PTA 3-wire Co-existence

    Enable connecting two devices via GPIOs, with Wi-Fi as primary and external BLE as secondary, ensuring better performance on the same radio without interference. The solution relies on a radio-sharing mechanism using request, priority, and grant signals. The PTA secondary manages the request and priority, while the PTA primary handles the grant to ensure optimal performance without interference.

    		 GA

    API Reference Guide - Wi-Fi Client
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Note: Flow control must be disabled to support PTA in NCP mode.

    Wi-Fi - Throughput
    Wi-Fi + Zigbee / OpenThread PTA 3-wire Co-existence

    Enable connecting two devices via GPIOs, with Wi-Fi as primary and external Zigbee or OpenThread as secondary, ensuring better performance on the same radio without interference. The solution relies on a radio-sharing mechanism using request, priority, and grant signals. The PTA secondary manages the request and priority, while the PTA primary handles the grant to ensure optimal performance without interference.

    		 GA

    API Reference Guide - Wi-Fi Client
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    Note: Flow control must be disabled to support PTA in NCP mode.

    Wi-Fi - Throughput

    SiWx91x Platform#

    Security | Firmware Update | Cryptography | Power Save | Peripherals | Services | Drivers

    Security#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Secure Boot

    Allow only authenticated and trusted firmware to execute during device startup.

    		 GA

    None
    • Firmware variants: Standard
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    Multiple examples
    PUF

    Secure key storage and hardware device identity

    		 GA
    • sl_si91x_puf_aes_encrypt_req
    • sl_si91x_puf_aes_decrypt_req
    • Firmware variants: Standard
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    Crypto - PUF
    Secure Zone

    An isolated area that protects sensitive code and data from unauthorized access.

    		 GA

    None
    • Firmware variants: Standard
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    Multiple examples
    Secure XIP

    Secure XIP (execution in place) from flash.

    		 GA

    None
    • Firmware variants: Standard
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    None
    Secure Attestation

    Verify device authenticity by exchanging a random nonce with the network processor and validating the signed response token to confirm device integrity.

    		 GA

    None
    • Firmware variants: Standard
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    Crypto - Attestation
    Anti-rollback

    Prevent a device from being downgraded to older firmware versions, ensuring only the latest authorized firmware can be installed and executed.

    		 GA

    None
    • Firmware variants: Standard
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    None
    Debug Lock

    Disable access to the device’s debug interface to prevent unauthorized debugging.

    		 GA

    None
    • Firmware variants: Standard
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    None
    Flash Protection

    Restrict access to specific regions of flash memory to prevent unauthorized access or modification.

    		 GA

    None
    • Firmware variants: Standard
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    None
    Firmware Update#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Firmware Loading with Simplicity Commander

    Load firmware using Simplicity Commander through Jlink Debugger connected to Serial Wire Debug (SWD).

    		 Beta

    API Reference Guide - Firmware Update From Host
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    None
    Firmware Loading through UART and SPI

    Load firmware via ISP using UART interface (Simplicity Commander or serial terminal) or SPI interface.

    		 Beta

    API Reference Guide - Firmware Update From Host
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - NWP Or Combined (NWP & M4) Firmware Update via TCP
    Secure Over-the-Air (OTA) Update

    Perform OTA firmware update via Wi-Fi from a remote HTTP/HTTPS server.

    		 Beta

    API Reference Guide - Firmware Update from Module
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: UART, SPI

    Wi-Fi - HTTP/HTTPS OTAF Update
    Firmware Update via Bootloader

    Update firmware from the host MCU using XMODEM protocol.

    		 Beta API Reference Guide - Firmware Update From Host
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI

    Wi-Fi - Firmware Flashing from Host UART
    Combined Image Update

    Secure and non-secure combined image update

    		 Beta

    API Reference Guide - Firmware Update From Host
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC only
    • Host interfaces: UART, SPI

    Wi-Fi - NWP Or Combined (NWP & M4) Firmware Update via TCP
    Cryptography#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Crypto Hardware Accelerators

    Crypto Hardware Accelerators for:

    • Advanced Encryption Standard (AES) 128/256/192
      • ECB
      • CBC
      • CTR
      • CCM
    • Secure Hash Algorithm (SHA) 160/224/256/384/512
    • Hash Message Authentication Code (HMAC)
    • SHA3/SHAKE
    • AES-Galois Counter Mode (GCM)/ Cipher-based Message Authentication Code (CMAC)
    • ChaChaPoly
    • True Random Number Generator (TRNG)
    • ECDH
    • PUF-IID
    		 GA

    API Reference Guide - Crypto
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART
    Crypto Software Accelerators

    Crypto Software Accelerators for:

    • RSA
    • ECC
    • ECDSA
    		 GA

    API Reference Guide - Crypto
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART

    Crypto - ECDSA
    PSA Crypto

    For all crypto operations except PUF-IID

    		 GA

    API Reference Guide - Crypto
    • Firmware variants: Standard and Lite
    • OPNs: Applicable OPNs
    • Boards: Applicable boards
    • Modes: SoC only
    • Host interfaces: N/A
    Wrapping Support

    Wrapping support for:

    • AES
    • ChaCha-Poly
    • HMAC
    • GCM
    • CMAC
    • ECDSA
    • TLS connection

    Note: Device security should be enabled. See the SiWx917 SoC Manufacturing Utility User Guide.

    		GA

    API Reference Guide - Crypto
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC, NCP
    • Host interfaces: SPI, UART
    Power Save#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Deep Sleep

    Application processor deep sleep with and without RAM retention, corresponding to the PS0 power state

    		 GA

    API Reference Guide - Power Manager
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    Power States

    Switch the application processor between multiple available power states:

    • Active: PS4, PS3, and PS2
    • Standby: PS4, PS3, and PS2
    • Sleep: PS4, PS3, and PS2
    • Power state with RAM retention and network processor (NWP) shutdown
    		 GA

    API Reference Guide - Power Manager
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    Peripherals#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Analog-to-Digital Converter (ADC)

    Convert analog signals into digital data, enabling interaction with real-world sensors such as temperature, light, and joystick.

    		 GA

    API Reference Guide - ADC

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    Analog Comparator

    Compare two analog input voltages via two input pins, and trigger an interrupt when non-inverting is higher than inverting.

    		 GA

    API Reference Guide - Analog Comparator

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - Analog Comparator
    BOD

    Nano Power BOD consisting of a comparator, reference buffer, scaler, and resistor bank.

    		 Beta

    API Reference Guide - BOD

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - BOD
    Config Timer

    Configurable timers used for various tasks such as modulated signal output, event capture on GPIOs in input mode, clock and event counting, and so on.

    		 GA

    API Reference Guide - Config Timer

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - Config Timer
    CRC

    Cyclic Redundancy Check (CRC) generation on DMA-transferred data

    		 GA

    API Reference Guide - CRC

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - CRC
    Digital-to-analog Converter (DAC)

    Convert digital data into analog signals, for use cases such as audio, telecom, and control systems requiring precise analog output.

    		 GA

    API Reference Guide - DAC

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - DAC
    eFuse

    One-time programmable memory element used to store configuration or data, with each eFuse using 32-bit addressing, with 8 bits of data per address, and accessed via an eFuse controller for programming and reading.

    		 GA

    API Reference Guide - eFuse

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - eFuse
    GPIO

    Configure and control GPIO pins for tasks like reading digital inputs, controlling devices, and handling interrupts.

    		 GA

    API Reference Guide - GPIO

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    GPDMA

    Memory-to-memory transfers of configurable sizes using either predefined configuration or a user-defined descriptor. Transfer size can be adjusted using TRANSFER_LENGTH.

    		 Alpha

    API Reference Guide - DMA

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - GPDMA
    GSPI

    Enable high-speed, full-duplex communication with SPI-compatible devices using a four-wire synchronous protocol, for both control and data messages.

    		 GA

    API Reference Guide - GSPI

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - GSPI
    Hardware Random Number Generator (HRNG)

    Generate high-quality random numbers using dedicated hardware entropy sources.

    		 GA

    API Reference Guide - HRNG

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - HRNG
    HSPI Secondary

    Integrate HSPI secondary with GPDMA to ensure reliable communication with a SPI primary device and efficient handling of HSPI operation callbacks.

    		 GA

    API Reference Guide - HSPI Secondary

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - HSPI Secondary
    I2C

    Two-wire serial protocol commonly used in microcontrollers for efficient communication with sensors and peripherals, ideal for systems with limited I/O pins.

    		 GA

    API Reference Guide - I2C

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    Inter-IC Sound (I2S)

    Serial protocol used to transmit digital audio between ICs, commonly connecting components like DSPs, DACs, and microphones

    		 GA

    API Reference Guide - I2S

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    Motor Control PWM (MCPWM)

    Generates programmable pulse waveforms for motor and power control, operating as a timer with a configurable period and duty cycle.

    		 GA

    API Reference Guide - PWM

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - PWM
    OPAMP

    Analog component that can be configured for various applications such as signal amplification, buffering, and voltage comparison

    		 GA

    API Reference Guide - OPAMP

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - OPAMP
    PSRAM

    A PSRAM combines DRAM density with SRAM-like ease of use by handling internal refresh automatically. The application processor (M4) accesses its internal PSRAM via a Quad-SPI interface.

    		 GA

    API Reference Guide - PSRAM

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    QEI

    Measure the position and speed of a rotating encoder, for applications requiring precise motion control.

    		 GA

    API Reference Guide - QEI

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - QEI
    Secure Digital Input/Ouput (SDIO) Secondary

    Device extending the SD card standard to support I/O functions, acting as a secondary to exchange data with an external SDIO primary.

    		 GA

    API Reference Guide - SDIO

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - SDIO Secondary
    Synchronous Serial Interface (SSI) Primary and Secondary

    Enable clock-synchronized serial communication between a microcontroller and peripherals, typically using SPI or microwire.

    		 GA

    API Reference Guide - SSI

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    Bipolar Junction Transistor (BJT) Temperature Sensor

    Convert a digital output into a temperature in measured in degrees Celsius.

    		 GA

    API Reference Guide - BJT Temperature Sensor

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - BJT Temperature Sensor
    USART

    Communicate with an external host through a wired connection in both asynchronous modes and synchronous modes, supporting using both full-duplex and half-duplex (single-wire) communication.

    		 GA

    API Reference Guide - USART

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    Ultra-low Power (ULP) ADC

    Converts analog signals into digital data, enabling interaction with real-world sensors like temperature, light, and joystick.

    		 GA

    API Reference Guide - ADC

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP ADC
    ULP DAC

    Convert digital data into analog signals, for use cases such as audio, telecom, and control systems requiring precise analog output.

    		 GA

    API Reference Guide - DAC

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP DAC
    ULP DMA

    Memory-to-memory transfers of configurable sizes using either a predefined configuration or a user-defined descriptor. Transfer size can be adjusted via TRANSFER_LENGTH.

    		 GA

    API Reference Guide - DMA

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP DMA
    ULP GPIO

    Configure and control GPIO pins for tasks like reading digital inputs, controlling devices, and handling interrupts.

    		 GA

    API Reference Guide - GPIO

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP GPIO
    ULP I2C

    Two-wire serial protocol commonly used in microcontrollers for efficient communication with sensors and peripherals, ideal for systems with limited I/O pins.

    		 GA

    API Reference Guide - I2C

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP I2C
    ULP I2S

    Serial protocol used to transmit digital audio between ICs, commonly connecting components like DSPs, DACs, and microphones.

    		 GA

    API Reference Guide - I2S

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP I2S
    ULP Timer Timer for extremely low-power operation, for use in battery-powered or energy-efficient devices GA

    API Reference Guide - ULP Timer

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP TIMER
    ULP USART

    Device for communication through a wired connection in both asynchronous mode and synchronous mode, with full-duplex and half-duplex (single-wire) connections.

    		 GA

    API Reference Guide - USART

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP UART
    ULP Synchronous Serial Interface (SSI) Primary

    Enable clock-synchronized serial communication between a microcontroller and peripherals, typically using SPI or microwire.

    		 GA

    API Reference Guide - SSI

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - ULP SSI PRIMARY
    UULP Real-Time Clock (RTC) or Calendar Device for accurate timekeeping and calendar functionality, enabling applications to track date and time, schedule events, and manage alarms in low-power modes. GA

    API Reference Guide - Calendar

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A
    UULP Watchdog Timer

    Trigger an interrupt or system reset on timeout due to failures like electrostatic discharge (ESD) or software errors, and also wake up the system from a Sleep or Standby state.

    		 GA

    API Reference Guide - Watchdog Timer

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - Watchdog Timer
    UULP System Real-Time Clock (SysRTC) Device providing precise timekeeping and timer functionality essential for various applications and tasks that require accurate time measurement, event scheduling, and power management. GA

    API Reference Guide - SysRTC

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host Interfaces: N/A

    SL Si91x - SysRTC
    Services#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    Sleep Timer

    Service providing software timers using a low-frequency real-time clock peripheral (SysRTC).

    		 GA

    API Reference Guide - Sleep Timer
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    SL Si91x - Sleep Timer

    I/O Stream

    Service used for configuring I/O Stream USART in asyncronous mode to send and receive data.

    		 GA

    API Reference Guide - I/O Stream
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    SL Si91x - I/O Stream USART Baremetal

    NVM3

    Service providing third-generation Non-Volatile Memory (NVM3) data storage on SiWx91x using both common flash and dual flash storage systems.

    		 GA

    API Reference Guide - NVM3
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A
    LittleFS

    Service providing basic file operations using the LittleFS library on a QSPI-based flash file system.

    		 GA

    API Reference Guide - LittleFS
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A
    Power Manager

    Service providing the management of low-power states, including state transitions (PS4, PS3, and PS2) and sleep-wakeup (PS4, PS3, and PS2 sleep with RAM retention), with and without tick-less idle mode

    		 GA

    API Reference Guide - Power Manager
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A
    Sensor Hub

    Service providing a convenient framework to integrate sensors on I2C, GPIO, UART, and ADC interfaces. It supports sensor activity in low-power mode

    		 Alpha

    API Reference Guide - Sensor Hub
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    SL Si91x - Sensor Hub
    Co-processor Communication (CPC)

    Low-power communication interface for an external host to access sensors over I2C, GPIO, UART, or ADC interfaces

    		 Alpha

    None
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: SDIO

    SL Si91x - CPC Secondary SDIO FreeRTOS
    Pin Tool

    Tool that enables configuration of GPIO pins and selection of supported peripheral combinations.

    		 Alpha

    None
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    None
    Drivers#
    Feature Name Description Quality Related API Names Supported Software Variants, Hardware, Modes, Host Interfaces Related Example Names
    LED

    Driver providing GPIO/LED toggle functionality

    		 GA

    API Reference Guide - GPIO

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    SL Si91x - Blinky
    Button

    Driver providing the use of buttons in a bare-metal environment.

    		 GA

    API Reference Guide - Button

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    SL Si91x - Button Baremetal
    Memory LCD

    Driver providing the use of the Memory Liquid Crystal Display (MEMLCD) module in a bare-metal application, using Silicon Labs Graphics Library (glib)

    		 GA

    API Reference Guide - Memory LCD

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    SL Si91x - Memory LCD Baremetal
    Joystick

    Driver providing the use of the joystick device

    		 GA

    API Reference Guide - Joystick

    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    SL Si91x - Joystick
    Mic

    Driver providing features such as starting and stopping audio capture, streaming audio data, and calculating sound levels from captured audio samples.

    		 GA

    API Reference Guide - Mic
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    SL Si91x - Mic
    On-board Sensors

    Driver providing access to features such as temperature and humidity measurements, ambient light Lux measurement, and 6-axis motion detection, using the following sensors:

    • Si70XX RHT Sensor
    • VEML Sensor
    • ICM Sensor
    		 GA
    • Firmware variants: Standard and Lite
    • OPNs: All
    • Boards: All
    • Modes: SoC
    • Host interfaces: N/A

    Unsupported Features#

    Wi-Fi | Network Stack | SiWx91x Bluetooth LE | Multiprotocol | SiWx91x Platform

    Wi-Fi#

    • SDIO host interface is not supported in NCP mode.

    • WMM-PS / UAPSD is not supported.

    • UL MU-MIMO is not supported.

    • 40 MHz bandwidth for 2.4 GHz band is not supported.

    • The number of non-transmitting BSSIDs processed is limited by the beacon length (1024 bytes) that can be processed by the Wi-Fi networking layers on the SiWx91x device. Beacons greater than 1024 bytes in length will not be processed.

    • WPA3 access point supports only the H2E algorithm.

    • SA query procedure not supported in 11W access point mode.

    • Access point standalone mode does not support TX aggregation. RX aggregation is supported with limited number of BA sessions.

    • In concurrent access point mode, aggregation (TX/RX) is not supported.

    • Low-power scan only supports the reception of 1 Mbps packets.

    • bTWT, Intra PPDU power save and spatial re-use features are not supported.

    • For WPA3 Enterprise connection in station mode:

      • EAP-192 bit mode is not supported.

      • UOSC is not supported.

      • PEAPV1 is not supported.

      • PMK caching is not supported.

      • Explicitly configured server certificate, server domain (FQDN), and server domain suffix configuration are not supported for server certificate validation.

    Network Stack#

    • Azure MQTT is not supported in asynchronous mode. This will be addressed in a future release.

    • Secure SSL re-negotiation is not supported in the offloaded network stack (the network stack on the network processor).

    • Dual-host mode is not supported.

    • TLS 1.3 server is not supported.

    • More than 3 SSL sockets are not supported in Wi-Fi-alone and Wi-Fi + BLE co-existence modes. The number of SSL sockets supported in Wi-Fi + BLE co-existence mode are determined by the RAM memory configuration selected.

    • In SSL, the ECC Curve ID supported is 23. SSL handshake with third-party clients depends on the SSL ECC Curve ID.

    • Timeout value of less than 1 second is not supported for socket select and receive APIs.

    • HTTP / HTTPS server is not supported in the offloaded network stack.

    • Auto PAC Provisioning in EAP-FAST with TLS 1.2 is not supported.

    SiWx91x Bluetooth LE#

    • Dynamically disabling or enabling BLE is not supported.

    • 8 concurrent peripheral and 2 concurrent central connections are supported with the following restrictions:

      • Only with the SL_SI91X_EXT_FEAT_480K_M4SS_192K RAM configuration (490 KB memory processor + 192 KB application processor),

      • Only with network processor power save enabled

      • Not on the PSRAM radio board (SiWx91x-RB4342A).

      • Not in NCP mode

      • Not with an encrypted connectivity (network processor) firmware image

    • The ae_central and ae_peripheral example applications are not supported with TA_352K_M4_320K RAM configuration (352 KB network processor + 320 KB application processor).

    • Isochronous channels are not supported.

    • Connection sub-rating is not supported.

    • LE power controller is not supported.

    • EATT is not supported.

    • Periodic Advertising with a response is not supported.

    • BLE Audio is not supported.

    • Dynamically changing the TX power is not supported when extended advertising is active.

    • The Simplicity Connect Mobile app does not support differentiating between the BLE configurators based on the Bluetooth device address.

    • Support for PSRAM examples is not available for all PSRAM variants. A few BLE PSRAM example are only supported with:

    • PSRAM is not supported with the ble_iop_app example application.

    • Over-the-air (OTA) firmware update with/without ACK is not supported with the ble_iop_app example application.

    Multiprotocol#

    • Wi-Fi Access Point (AP) + BLE co-existence mode is currently not supported.

    • EXT_FEAT_352K_M4SS_320K RAM configuration (352 KB network processor + 320 KB application processor) is not supported for co-existence mode with SSL.

    • Over-the-air (OTA) firmware update with BLE is not supported.

    • Wi-Fi + BLE with 8 concurrent peripheral and 2 concurrent central connections is supported with the following restrictions:

      • Only with SL_SI91X_EXT_FEAT_480K_M4SS_192K RAM configuration (480 KB network processor + 192 KB application processor).

      • Only with network processor power save enabled

      • Only with the MQTT profile (Wi-Fi MQTT data transfers of ~200 bytes each every 1.5 seconds)

      • Not on the PSRAM radio board (SiWx91x-RB4342A).

      • Not in NCP mode

      • Not with an encrypted connectivity (network processor) firmware image

      • Not with IPv6

      • Not with Target Wake Time (TWT) based wakeup

      • Not with RPA

    • For Wi-Fi + BLE with 8 concurrent peripheral and 2 concurrent central connections:

      • The minimum connection interval for all the 8 BLE peripheral connections (SiWx91x as central) should be 200 ms.

      • The first BLE central connection interval (SiWx91x as peripheral) should be at least 45 ms.

      • The second BLE central connection interval (SiWx91x as peripheral) should be at least 500 ms.

      • A minimum supervision timeout of 8 seconds is mandatory for all BLE connections.

      • The BLE advertising interval should be configured to 211.25 msec.

      • The BLE scan window and scan interval should be in a 1:3 ratio.

      • SMP pairing is limited to I/O-Capabilities 0x01 and 0x03.

    • Wi-Fi + AE BLE with 2 concurrent (either 2 central, 2 peripheral, or 1 central and 1 peripheral) connections is supported with the following restrictions:

      • Only with SL_SI91X_EXT_FEAT_480K_M4SS_192K RAM configuration (480 KB network processor + 192 KB application processor) and SL_SI91X_EXT_FEAT_416K_M4SS_256K configuration (416 KB network processor + 256 KB application processor).

      • Only with network processor power save enabled.

      • Not on the PSRAM radio board (SiWx91x-RB4342A).

      • Not with an encrypted connectivity (network processor) firmware image.

      • Not with Target Wake Time (TWT) based wakeup.

      • Not with RPA.

      • Not with periodic advertising.

    • For Wi-Fi + AE BLE with 2 concurrent (either 2 central, 2 peripheral, or 1 central and 1 peripheral) connections:

      • The scan window and interval should be in a 1:3 ratio.

      • Maximum of 2 advertising sets are supported.

      • Maximum supported AE data length is 200 bytes.

    SiWx91x Platform#

    • BOD Peripheral in PS2 state is not supported.

    • 16 MB Flash is not supported.

    • 16 MB PSRAM is not supported.

    • 1.8 V Supply is not supported.

    • Bare-metal mode is not supported.

    • Zephyr is not supported.

    • Depending on the crypto engine in use, except HMAC and SHA/SHA3, the input message length limit must not exceed its defined maximum. Refer to the crypto engine's documentation or SDK specifications for exact limits and details.

    • Multi-part is not supported for AES-GCM due to hardware limitations.

    • FreeRTOS tick-less idle power save mode is not supported with the Sensor Hub example application.

    • PS1 state is not fully implemented for all supported wakeup sources in the Power Manager.

    • The manual chip select option is not supported when using GSPI.

    • Multi-secondary mode is not supported when using SSI Primary.

    • Dual and quad modes are not supported when using SSI Primary.

    • The config timer peripheral does not support a 32-bit timer.

    • Config timer features to trigger DMA and interrupts on events or counters are not supported.

    • UART instances do not support different FIFO thresholds.

    • Lower baud rate bit-width 9 is not supported when using UART or USART.

    • Multi-channel mode and external event based sampling are not supported when using ADC.

    • MPU is not supported.

    • Using a 32 KHz external oscillator (connected to UULP GPIOs) will cause a timer drift in the Calendar and Watchdog Timer. This is the default configuration for SoC modules.

    • The API Reference Guide does not provide example application and API reference information for RSI-based peripherals.

    • The DMA controller does not support timeout or threshold interrupts for half-full or full states. For asynchronous transactions, the application must implement handshaking mechanisms to ensure proper synchronization and data transfer control.

    • For the Co-Processor Communication (CPC) driver:

      • Once the kernel module is installed, re-loading of the module is not supported.

      • Once the daemon connection is successful between the Linux Host and CPC secondary, exiting and re-running the daemon is not supported.

    • WatchDog timer is not operational during power save.

    • For the OPAMP peripheral:

      • SL Layer support for the OPAMP peripheral can support only 5 out of 10 features: unity gain, inverting PGA, non-inverting PGA, inverting with Hysteresis Comparator, and non-inverting with Hysteresis Comparator.

      • GPIO 27 (Top GPIO), ULP_GPIO_2 and ULP_GPIO_4 are not supported.

      • The Pin Tool is not supported for all OPAMP instances.

    SDK Release and Maintenance Policy#

    See here for our SDK release and maintenance policy.