Cloud connectivity is much discussed nowadays, especially given its various advantages, e.g.:

• Increased accessibility of Cloud-connected devices;
• Enhanced backup options for critical data;
• Strengthened device security and reduced maintenance costs due to Over-The-Air (OTA) updates;
• Improved productivity due to automation and increased collaboration between different devices (Machine-to-Machine).

These well-known advantages are making the technology widely accepted across various industries, so much so that “Over 60% of organisations currently use IoT, with only 9% of them currently having none at all.” (IoT Developer Survey, Eclipse Foundation[1])

But still, according to the GSMA Intelligence Enterprise IoT Survey[2], there are challenges facing IoT advocates, such as the integration of IoT with existing technologies and the cost of its implementation.

Challenges to the adoption of IoT technologies by enterprises.

ESP-Hosted is Espressif’s solution to the integration complexities of IoT technologies and the consequent development costs. ESP-Hosted requires no or minimal changes to existing technologies, while also being an open-source solution which works off-the-shelf, thus lowering development costs.

To be more precise, ESP-Hosted offers a way of using Espressif SoCs and modules as communication co-processors. This solution provides wireless connectivity (Wi-Fi and Bluetooth / Bluetooth LE) to the host microprocessor (MPU) or microcontroller(MCU), allowing it to communicate with other devices. ESP-Hosted communicates with the host processor through the commonly available UART, SPI or the SDIO peripheral interface.

The High Level Architecture of ESP-Hosted

This architecture which separates the wireless connectivity module from the main host-processing module adds wireless connectivity to existing MCU/MPU-based solutions and, therefore, has the following advantages:

• • Faster development cycles: ESP-Hosted helps the connectivity module to function over the standard 802.11 interface (ESP-Hosted-NG) or an 802.3 interface (ESP-Hosted-FG). This way, ESP-Hosted functions as a plug-and-play device.
  • Reduced re-qualification/re-certification efforts: Since ESP-Hosted does not touch upon user-space applications, adding the connectivity module does not require developers to re-qualify or re-certify the majority of their software.
  • Power Saving: The main MPU/MCU can remain in low-power mode continuously, while also staying connected to the network. Thus, the main host needs to get involved only when there are actual tasks, e.g., the offloading of all connectivity overheads to the connectivity module.
  • Easier upgrades and product variants: The architecture enables developers to easily upgrade their products’ wireless connectivity or have multiple variants of the same product with different connectivity options. Such an example is shown below, where the developer can use the same Host applications and software, yet with a variety of wireless-connectivity options ranging from Wi-Fi4 to Wi-Fi6 or Wi-Fi6 dual band.

Example of the same Host Application with different connectivity modules

On this note, Espressif has made the source code of ESP-Hosted freely available, so that developers may easily take advantage of the various features of ESP32. Developers can also benefit from the IO and HMI capabilities of ESP32 and ESP32-S3, or the advanced security features of ESP32-C3, i.e. the Digital Signature Peripheral of the device. Therefore, the possibilities are endless.

Variants of ESP-Hosted

The ESP-Hosted solution is available in two variants, ESP-Hosted-FG and ESP-Hosted-NG The difference between them is the type of network interface presented to the host, and the way Wi-Fi on the ESP SoC/module is configured/controlled. Both variants have their respective host and firmware software.

ESP-Hosted-FG

This variant provides a standard 802.3 (Ethernet) interface to the host. In order to achieve this, the host is presented with the following:

• • A simple 802.3 network interface which essentially is an Ethernet interface;
  • A lightweight control interface for configuring Wi-Fi on the ESP SoC;
  • A standard HCI interface.

The use of the simple 802.3 interface with this solution makes it ideal for MCU hosts. The MCU application can continue to take advantage of the standard TCP/IP stack and prevent significant changes to the host application when using the AT firmware-based approach or when integrating the complex 802.11 interface.

ESP-Hosted-NG

This variant is specifically designed for hosts that run a Linux operating system by taking a standard approach while providing a network interface to the host. This allows the use of standard Wi-Fi applications, such as wpa_supplicant, to be used with ESP SoCs/modules. This solution offers the following:

• • 802.11 network interface, which is a standard Wi-Fi interface on a Linux host;
  • The configuration of Wi-Fi is supported through a standard cfg80211 interface on Linux;
  • A standard HCI interface.

Our Recommendation

• • If you use an MCU host, you should use ESP-Hosted-FG.
  • If you use a Linux host, we recommend ESP-Hosted-NG, because it takes a standard approach which makes it compatible with widely used user space applications/services, such as wpa_supplicant, Network Manager etc.

References 


1. IoT Developer Survey, Eclipse Foundation

2. GSMA Intelligence Enterprise IoT Survey