Integrating wireless modules into application software tends to be an interesting project. Microchip's RNWF02 provides an attractive solution using the AT command set for data exchange between the Wi-Fi module and the host microcontroller, leading to a greatly simplified integration process.

Microchip's RNWF02 Wi-Fi module is documented at https://onlinedocs.microchip.com/oxy/GUID-3DDF7D25-768C-4E66-8343-E56E3AE4B4BB-en-US-1/index.html, and provides a unique hardware interface. A practical implementation would present itself as follows, with two serial lines enabling communication with the host;

The embedded firmware of the module interprets AT commands similar to the ones used in the well-known Hayes modem interface. The 8, 16, or 32-bit microcontroller application sends strings via a wireless interface, which are then transformed into commands for the wireless transmitter on the module.

In terms of hardware, Microchip provides four variants of the module with and without an onboard antenna. 

Off-board Wi-Fi network stack with advanced capabilities

The module handles networking operations in a completely autonomous fashion. Once a command is received over the serial interface, the communication with servers, access points, and other hardware is transparent to the microcontroller.

This expands to higher-level protocols and in the documentation, Microchip announces support for the MQTT protocol suite. Furthermore, power consumption is managed via magic-packet-based snoozing and with incompatible Wi-Fi infrastructure, power consumption is reduced.

Finally, the RNWF02 boasts formidable cryptography-accelerator functionality. The datasheet illustrates the Microchip RNWF02 is well-equipped in terms of cryptographic acceleration.

While the module is still being developed, hardware developers seeking integration can use an advanced evaluation kit.

As shown in the figure, it is an evaluation board bearing a prototype module along with a microBus interface intended for communication with external hardware.

The RNWF02 is part of the mikroE ecosystem and when purchased, the board comes with a Python-based, out-of-the-box demonstration intended to connect the system to Microsoft's Azure IoT Central service. Developers interested in learning more about how the device is to be programmed can visit the source code on GitHub, which is available at https://github.com/MicrochipTech/RNWFxx_Python_OOB. In addition, a programming manual for the part can be found at the URL https://onlinedocs.microchip.com/oxy/GUID-D0CB3D06-2ABE-4892-963E-65CAE080D507-en-US-1/index.html.

Microchip is actively working on the rollout of the development board and those developers currently seeking to deploy it in their practical projects can purchase the hardware from Microchip Direct and Mouser.

With the RNWF02, Microchip provides a network helper module to simplify developer life. Its AT command set requires minimal hardware resources on the host microcontroller. If wireless connectivity has to be added to an existing application, this unit is the best solution on the market.