ST Microelectronics SPWFS04 Users Manual

SPWF04SA
SPWF04SC

Serial-to-Wi-Fi b/g/n intelligent modules

Features



2.4 GHz IEEE 802.11 b/g/n transceiver



STM32 ARM Cortex-M4, with 256 KB RAM
and

2 M

B Flash memory



Integrated TCP/IP protocol stack
–

2 (TBC) simultaneous TCP or UDP
clients and 2 (TBC) socket server

–

supporting up to TLS 1.2, including
common encryption algorithms: AES
(128, 256), hash (MD5, SHA-1, SHA-

256) and public key algorithms (RSA,
ECC)

–

Web server supporting dynamic web pages



WEP/WPA/WPA2 personal and enterprice
security



System modes: Station, IBSS, and miniAP



miniAP easily provisioned (SSID, PWD)



Fast Wi-Fi reassociation after reset



Firmware update via UART and Over The Air
(FOTA



TX power
–

18.3 dBm @ 1 Mbps DSSS

–

13.7 dBm @ 54 Mbps OFDM



RX sensitivity
–

-96.0 dBm @ 1 Mbps DSSS

–

-74.5 dBm @ 54 Mbps OFDM



16 configurable GPIOs available



UART and SPI interface to host system



Advanced low-power modes
–

Standby with RTC: 0.8mA (TBC)

–

Sleep connected (DTIM=1): 19 mA

–

RX traffic 113 mA typical

–

TX traffic 248 mA typical @ 18 dBm



Simple AT command set host interface through
UART



Small form factor: 26.92 x 15.24 x 2.35 mm



Single voltage supply (3.3 V typical)



Multiple antenna options:
–

Integrated antenna (SPWF04SA
versions)

–

Integrated u.fl connector (SPWF04SC
versions)



Industrial temperature range: -40 °C to 85 °C



FCC/CE/IC/SRRC certified



RoHS compliant



Surface mount PCB module

Applications



Smart appliances



Industrial control and data acquisition



Home automation and security systems



Wireless sensors



Cable replacement



Medical equipment



Machine-to-machine communication

April 2016 DocID025635 Rev 7 1/18

.

Preliminary Datasheet

www.st.com

Description

SPWF04SA, SPWF04SC

2/18

DocID025635 Rev 7

1

Description

The SPWF04SA and the SPWF04SC intelligent Wi-Fi modules represent a plug-and-play
and standalone 802.11 b/g/n solution for easy integration of wireless Internet connectivity
features into existing or new products.

Configured around a single-chip 802.11 transceiver with integrated PA and comprehensive
power management subsystem, and an STM32 microcontroller with an extensive GPIO
suite, the modules also incorporate timing clocks and voltage regulators. Two different
options exist based on the integrated Flash memory.

The module is available either configured with an embedded micro 2.45 GHz highly-efficient
ISM band antenna (SPWF04SA), or with an u.fl connector for external antenna connection
(SPWF04SC).

With low power consumption and 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, such as REST API for
accessing files on servers in the cloud and support for dynamic web pages with CGI/SSI
functions to easily interact with the module and the host processor over the air.

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 AN4683 (TBC) for details.

The SW package also includes an AT command layer interface for user-friendly access to
the stack functionalities via the UART serial port. For details, see user manual UM1695
(TBC).

It is always possible to upgrade the module firmware via UART and Over The Air (FOTA).
Inside of the 2 MB extended Flash available on the SPWF04S module, 1 MB of the Flash is
dedicated to FW upgrade and to host proprietary files, organized in a file system image,
accessible through the integrated web server.

FOTA is also possible with the SPWF04Sx module.
ST may update the FW provided with the modules at any time. ST recommends that users

regularly check for documentation and the current FW version available at

www.st.com/wifimodules.

SPWF04SA, SPWF04SC

Description

Figure 1. Block diagram

DocID025635 Rev 7 3/18

General electrical specifications

SPWF04SA, SPWF04SC

Parameter

Test condition/comment

Min.

Typ.

Max.

Unit

Voltage supply

-

-0.3

-

4.0

V

Vin for 5 V tolerant pins

-0.3

5.5

V

Vin for all other pins

-0.3

3.6

V

Storage temperature range

-55

105

°C

Parameter

Test condition/comment

Min.

Typ.

Max.

Unit

Operating temperature range

Industrial

-40 85

°C

3.3 V
supply

Input supply voltage

3.3 V supply input

3.1

3.3

3.6

V

Standby

Both the STM32 and the radio
are in standby power states

0.8

mA

Sleep

The STM32 is in stop power
state and the radio is in sleep
power state

19

mA

Low power state

The STM32 is active and the
radio is in sleep power state

52

mA

TX

802.11b
TX power=0 dBm

236 mA

TX power=10 dBm

250 mA

TX power=18 dBm

344 mA

802.11g
TX power=0 dBm

210 mA

TX power=10 dBm

243 mA

TX power=18 dBm

338 mA

RX

802.11b

105 mA

802.11g

105 mA

2

General electrical specifications

Table 2. Operating conditions and input power specifications

Table 1. Absolute maximum ratings

(1)

1.

Typical results are at room temperature only.

4/18 DocID025635 Rev 7

SPWF04SA, SPWF04SC

Digital interface specifications

Parameter

Test condition/comment

Min.

Typ.

Max.

Unit

Inputs

VIH

2.3

-

3.6

V

VIL

0

0.9

V

Outputs

VOH

IOH=4 mA

2.4

3.6

V

VOL

IOL=4 mA

0

0.4

V

3

Digital interface specifications

Table 3. Digital interface specifications, I/O pins

DocID025635 Rev 7 5/18

RF characteristics

SPWF04SA, SPWF04SC

Parameter

Test condition/comment

Min.

Typ.

Max.

Unit

11b, 1 Mbps

-96 dBm

RX sensitivity

(1)

11b, 2 Mbps

-93 dBm

11b, 5.5 Mbps

-91 dBm

11b, 11 Mbps

-87 dBm

11g, 9 Mbps

-89.5

dBm

11g, 18 Mbps

-86 dBm

11g, 36 Mbps

-80 dBm

11g, 54 Mbps

-74.5

dBm

11n, MCS1, 13 Mbps

-86.5

dBm

11n, MCS3, 26 Mbps

-81.5

dBm

11n, MCS5, 52 Mbps

-74 dBm

11n, MCS7, 65 Mbps

-71 dBm

Channel-to-channel
de-sensitivity

CH1 to 14

11g, 54 Mbps, 10%PER

1

dB

Maximum input signal

CH7

11g, 54 Mbps

-20 dBm

Adjacent channel rejection

11Mbps

38 dBc

9 Mbps

20 dBc

54 Mbps

4

dBc

MCS1

24 dBc

MCS7

3

dBc

TX output power

(1)

11b, 1 Mbps

@ 11b spectral mask

18.3

dBm

11b, 11 Mbps

18.3 dBm

11g, 9 Mbps

@ 11g spectral mask

18.3 dBm

11g, 54 Mbps

EVM = -27 dB, 4.5%

13.7 dBm

11n, MCS1

@ 11n spectral mask

18.3 dBm

11n, MCS7

EVM = -27 dB

13.5 dBm

On-board antenna gain

Average

-1.2 dBi

External antenna gain

SG901-1066 average
including cable loss

2.8

dBi

4

RF characteristics

Table 4. RF characteristics

1. Output power and sensitivities are measured with a 50 Ω connection at the antenna port.

6/18 DocID025635 Rev 7

SPWF04SA, SPWF04SC

Pinout description

Signal name

Type Pin number

Main function

Alternate

functions

(1)

Notes

GPIO - general purpose input/output

GPIO[0]

I/O

16

General purpose

input/output Restore to

factory

settings

(2)

Input pull down and

5V tolerant

GPIO[1]

I/O 17

General purpose

input/output/ADC

Input pull down and

5V tolerant

GPIO[2]

I/O 19

General purpose

input/output/PWM

Floating and 5V

tolerant

GPIO[3]

I/O 1

General purpose

input/output

Input pull down and

5V tolerant

GPIO[6]

I/O

22

General purpose

input/output Wake

Up/Sleep

Inhibit

(3)

Input pull down and

5V tolerant

GPIO[4]

I/O 18

General purpose

input/output

GPIO[5]

I/O 20

General purpose

input/output

GPIO[7]

I/O

13

General purpose

input/output STA/Mini

AP

Switch/WPS

Pushbutton

(4)

GPIO[8]

I/O 4

General purpose

input/output

GPIO[9]

I/O 7

General purpose

input/output/SPI

nHostInterrupt

GPIO[11]

I/O

11

GPIO[12]

I/O 12

General purpose

input/output

GPIO[15]

I/O 21

General purpose

input/output/DAC

Monitoring purpose with no alternate function

GPIO[10]

I/O 5

Drives LED, Blinks while

running

GPIO[13]

I/O 15

Drives LED, Wi-Fi link

up

5

Pinout description

Table 5. Pinout description

DocID025635 Rev 7 7/18

Pinout description

SPWF04SA, SPWF04SC

Signal name

Type Pin number

Main function

Alternate

functions

(1)

Notes

GPIO[14]

I/O 14

LED drive, Power

up

UART pins

RXD /
MOSI

I

8

5V tolerant

TXD /
MISO

6

5V Tolerant

CTS / nCS

I

9

Active low, 5V tolerant

RTS / CLK

O

10

5V tolerant

Reset

RESETn

I

3

Reset input

Active low for 5 ms

with pull up to

2.5VDC. Not 5V
tolerant

Supply pins and paddle

3.3 V

24

Voltage supply

Decouple with 10uF

capacitor

Ground 23

Ground

LSE 34

HSE 35

SWD I/O 26

SWD CLK

29

GPIO16 27

Not available

GPIO17 28

Not available

GPIO18 30

Not available

SDIO CLK /
SPI CLK

31

SDIO D0 /
SPI MISO

32

SDIO CMD
/ SPI MOSI

33

Ground Paddle

25

Ground

Add plenty of ground

vias for thermal

dissipation and ground

return

Boot loader

BOOT0 I 2

Boot loader

(5)

Table 5. Pinout description (continued)

1.

The activation of ALT function depends upon the firmware version or upon the variable configuration.

2.

To perform the factory reset of the variables, pin GPIO0 must be high during powerup.

3.

GPIO function running when low power mode variable is enabled.

4.

Introduced with the release 3.0 of AT Full stack. To enable the STAToMiniAP switch the GPIO[7] needs to be put low
together with the HW reset

8/18 DocID025635 Rev 7