Espressif’s SDKs pertaining to the ESP8266, ESP32, and ESP32-S2 series of chips contain various software components and tools for hassle-free IoT development.  Espressif continuously optimizes and updates its SDKs to meet its customers’ needs. That’s why Espressif has just released ESP8266 NonOS SDK v3.0.3. Customers who wish to continue using the ESP8266 NonOS SDK are advised to update their systems to the latest version, v3.0.3.

However, those who use ESP8266-based SoCs, modules and development boards should already be aware of the two existing SDKs for ESP8266. For those who are less familiar with the ESP8266-related SDKs, let us clarify the differences between the two.

ESP8266 NonOS SDK

The ESP8266 NonOS SDK is an early SDK for ESP8266 without an operating system. In December 2019, we released the support strategy for the ESP8266 NonOS SDK, announcing that no new features would be added. Indeed, the latest version, v3.0.3, contains only bug fixes and updates.

ESP8266 RTOS SDK

The ESP8266 RTOS SDK can meet diverse needs for IoT application development, as it is based on the FreeRTOS operating system, which is the most widely used non-Linux embedded operating system nowadays. As far as ESP8266 RTOS SDK V3.0 is concerned, Espressif has updated the system architecture, while the code has been adjusted so that it is consistent with ESP-IDF, Espressif’s IoT Development Framework. This means that the same set of application code can be used for the development of products with different Espressif chips (ESP8266, ESP32 and ESP32-S2).

The main performance characteristics of the latest ESP8266 RTOS SDK are listed below:

• • Support for cloud platforms such as Alibaba, JD.com, Tencent, Microsoft, and Amazon.
  • Support for backtrace, combined with idf_monitor, so that users can intuitively see the logic behind the function.
  • Use of the open-source Bootloader, which facilitates user research and integration.
  • Support for AWS IoT (Amazon), protobuf-c (Google), jsmn, system Log, newlib, NVS Flash, Partition management and Wi-Fi enterprise encryption.
  • Restructured Heap, hardware system scheduling process, high-speed startup, and other functions greatly improving the system’s operating efficiency.
  • Refactored, optimized and open-source SPI Flash, ADC, SPI master / slave, I2S, PWM, etc.
  • Added HTTP client / server, TCP transport and wifi_provisioning (distribution network), for extra user convenience.
  • Updated GCC to 5.2.0, and fixed the xtensa disassembly error.
  • Updated cJson, LwIP, mbedTLS to a newer and more stable version.
  • Users can directly compile (make), download (make flash) and debug (make monitor) firmware, as well as easily conduct firmware size analyses (make size).
  • Reduced power consumption of the system.


Upgrade Recommendations

Since the ESP8266 NonOS SDK is not scheduled to have any new features, our attention will be focused on further updating the ESP8266 RTOS SDK. If you wish to continue using either of our two ESP8266-related SDKs, here are a few helpful tips:

1. When you use ESP8266 to develop new products, we recommend that you stick to ESP8266 RTOS SDK.

2. For customers who use the old version of ESP8266 NonOS SDK, we recommend that you upgrade to the new IDF architecture of the ESP8266 RTOS SDK. The following links provide you with examples of how to upgrade your system:

• FOTA upgrade instructions
• FOTA upgrade example

3. For customers who already use the ESP8266 NonOS SDK for products in mass production, and who plan to continue using it thereafter, we recommend that you update to the latest version: ESP8266 NonOS SDK v3.0.3.


For any further technical support, please contact our team of engineers.