SPWF04SA, SPWF04SC

Description

DocID029757 Rev 5

5/27

1

Description

The SPWF04SA and the SPWF04SC are ready-to-use Wi-Fi modules conceived for

Internet of Things (IoT) applications. The modules integrate a Cortex-M4-based STM32

microcontroller and a powerful Wi-Fi transceiver, compliant with IEEE 802.11 b/g/n

standard for the 2.4 GHz band.

The modules are cloud compatible thanks to the complete protocol package, which

includes application and security layers. They can operate in serial-to-Wi-Fi and standalone

mode, with customer applications developed in the subsystem based on the MicroPython

environment.

The modules are configured around a single-chip 802.11 transceiver with integrated PA

and comprehensive power management subsystem, and an STM32F4 microcontroller with

UART/SPI interface and an extensive GPIO suite; they also incorporate timing clocks and a

voltage regulator.

The SPWF04SA module is configured with a highly-efficient, embedded micro 2.4 GHz ISM

band antenna, or with an external U.FL antenna connector (SPWF04SC); both are certified

FCC/IC and CE.

With low power consumption and an ultra-compact (2.7 x 1.5 cm) footprint, the modules are

ideal for fixed and mobile wireless applications, as well as challenging battery-operated

applications.

The SPWF04Sx parts are released with an integrated full featured TCP/IP protocol stack

with added web server and additional application service capabilities, including REST API

for accessing files on servers in the cloud and support for dynamic web pages with SSI

functions to easily interact with the module and the host processor over the air. Application

note AN4965 on www.st.com provides details on HTTP server capabilities.

Multiple higher level protocols over TCP are supported by the module including: HTTP,

MQTT, SMTP, and WebSockets to easily connect application to the cloud. Multiple

protocols supported over UDP include: TFTP, SNTP and mDNS; the module also includes

IPv6 networking capabilities.

The SW package also has an AT command layer interface for user-friendly access to the

stack functionalities via the UART serial port and an SPI interface supporting master and

slave messages from and to the host processor respectively (see user manual UM2114 on

www.st.com).

The SPWF04Sx includes a MicroPython scripting engine to enable simple and fast custom

application development on the module MCU: no external MCU is needed and the

customer application runs directly on the module. The interpreter implementation is fully

compatible with the standard MicroPython version 1.6. In standalone mode, MicroPython

use Wi-Fi interfaces and MCU peripherals such as UART, SPI, I2C, GPIOs via standard

MicroPython APIs (see application note AN4964 on www.st.com).

1 MB of the internal Flash is dedicated to store the user file system while a hardware

interface allows the usage of an external memory via SPI/SDIO (Serial Flash/SD Card) to

further extend the file system storage capabilities.

The module supports WPA2-Personal and WPA2-Enterprise security and WPS (Wi-Fi

protected setup).

For secure end-to-end communication with the cloud, an SSL/TLS stack is embedded in

every module, with no licensing charge. See application note AN4963 on www.st.com for

details on security.