“More is More“ When it Comes to Memory on Wi-Fi IoT Devices

Ask any IoT product developer how much memory their next design will need, and the answer will likely be, more is more! Unfortunately, tiny IoT footprints and constrained hardware resources do not often meet growing memory requirements. This blog describes how much memory IoT devices actually need, and how our SiWx917M Wi-Fi 6 SoCs respond to the IoT developers' call for more memory.

Despite their small sizes, IoT devices are equipped to run increasingly advanced applications in smart homes, buildings, hospitals, enterprises, and other smart areas of our modern societies. They can run multiple wireless protocol stacks such as Wi-Fi and Bluetooth Low Energy (LE). IoT devices can be connected to several ecosystems through the Matter application layer. Many types of IoT devices can operate autonomously for years in the field. During their operational lifetime, manufacturers push frequent over-the-air (OTA) software updates and security patches to keep their devices current and safe from cyber threats.

IoT Memory Challenge

The challenge for IoT device makers is how to enable all the necessary functions, including the wireless stacks and a complex application on constrained hardware resources, while also accommodating space for OTA updates and future code growth. Memory has become a critical bottleneck for IoT device makers. It's scarce hardware real estate. However, a large memory enables manufacturers to build better devices with more features and longer lifetime, and it also increases the total value and lifetime of their circuit designs.

This blog explains the IoT memory challenge for non-tech readers: how much memory do you need in an IoT device? How does the SiWx917M Wi-Fi 6 and Bluetooth LE SoC solve the memory challenge with its large memory configuration?

How Much Memory do IoT Devices Need?

IoT devices need memory for a couple of purposes:

• Wireless stacks: the protocol stacks such as Wi-Fi, Bluetooth LE, and Matter are fairly compact software components, yet they can occupy several hundreds of kilobytes of RAM and a few megabytes of Flash.
  

• Customer application: similarly, the (customer's) device application, whether a smart lock, temperature sensor, or light switch, can occupy hundreds of kilobytes of RAM and megabytes of Flash, depending on the complexity and the amount of data.

• Software updates: to ensure a fluent and quick execution of OTA software updates, ample space on the Flash must be reserved.

• Future code growth: software tends to grow over the lifetime of the device and manufacturers need to reserve room on the Flash for future code growth.

The Large Memory Configuration of the SiWx917M

The SiWx917M Wi-Fi 6 SoC features the largest memory configuration in the ultra-low-power Wi-Fi segment. But how much memory do you get with the SiWx917M SoCs, and what can you do with it? Continue reading for a quick description of the SiWx917M SoC memory configuration.

SiWx917M RAM Memory

The SiWx917M SoC features a large internal SRAM (static-RAM) memory of up to 672kB, providing you with more space to execute your application, a security engine, peripherals, Wi-Fi, Bluetooth LE, and Matter protocol stacks. There are three software-configurable memory options for sharing the SRAM between SILICON LABS'  wireless system and your application, allowing you to optimize SiWx917M for various use cases.

SiWx917M In-package Flash

With SiWx917M, you should not run out of flash memory. It provides you with up to 8MB of flash in several alternative configurations depending on the order part number (OPN) .

The large 8MB flash is required in many IoT devices to accommodate the wireless stacks, Matter protocol software, Master Boot Records, bootloader, certificates, OTA software updates, and future code growth.

With the large Flash of SiWx917M, you can develop better, and more advanced IoT devices. It also enables a single-chip architecture, where SiWx917M in SoC operational mode, runs the entire wireless system and your application, reducing device footprint, saving your total BoM and design costs. The large flash allows a longer operational lifetime for your device.

SiWx917M In-package PSRAM

In some cases, IoT software design may need more RAM memory than the 672kB that is available in SiWx917M. Luckily, SiWx917M supports pseudo-SRAM, expanding your execution space radically. The product family includes OPNs, which are equipped with up to 8MB of PSRAM instead of flash.

Note, if both Fash and PSRAM are needed, you can order our SiWx917Y modules, where you can find an OPN with both memory types.

SiWx917M External Flash and PSRAM Expansion

Should you need even more memory than the 8MB flash or PSRAM, SiWx917M supports an encrypted interface to an external flash or PSRAM of up to 16MB, offering ultimate design flexibility and space.

We are convinced that with the ultra-low-power SiWx917M Wi-Fi 6 and Bluetooth LE SoCs, you will have ample memory to accommodate all the functionalities of an advanced wireless IoT device, and you can still allocate space for Matter, OTA updates, and future code growth for the entire lifetime of your device!