WiFi 4 Click

How does it work?

WiFi 4 Click is based on the SPWF01SA, a serial-to-WiFi b/g/n intelligent module from STMicroelectronics. The module includes the 2.4GHz IEEE802.11 b/g/n transceiver and STM32 ARM Cortex-M3 microcontroller with 64KB RAM and 512KB Flash memory. It also has a chip antenna to connect successfully to the 2400MHz frequency band and can achieve up to +18dBm of output power. The SPWF01SA module features advanced low-power modes, firmware updates via the UART interface, FOTA (over-the-air), and a simple AT command set. Depending on the modulation, this Click board™ can achieve 1Mbps with DSSS or even up to 54Mbps using OFDM.

To communicate with the host MCU, the WiFi 4 Click uses the UART interface of the mikroBUS™ socket, with commonly used UART RX and TX pins. It also uses additional pins, such as the RST pin, that resets the WiFi module with a low logic state. The RTS and CTS pins go over unpopulated RTS and CTS solder jumpers to corresponding pins of the mikroBUS™ socket and can be used by the host MCU if shortening them. The unpopulated BOOT solder jumper can put the onboard STM32 MCU into bootloader mode. In addition, this Click board™ features HD1 and HD2 headers with SPWF01SA user-configurable GPIO pins. Besides its general-purpose functionality, pin 14 can also be used as a Power Up status pin for monitoring purposes. The module has a WiFi Link and Active LEDs to visually present module statuses.

This Click board™ can only be operated from a 3.3V logic voltage level. Therefore, the board must perform appropriate logic voltage conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Specifications

Pinout diagram

This table shows how the pinout on WiFi 4 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
Reset	RST	2	RST	INT	15	CTS	UART CTS
UART RTS	RTS	3	CS	RX	14	TX	UART TX
	NC	4	SCK	TX	13	RX	UART RX
	NC	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

WiFi 4 Click electrical specifications