Usr USR-WIFI232-G User manual

Low Power WiFi Module User Manual V1.3 http://www.tcp232.net
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Low Power WiFi Module User Manual
(USR-WIFI232-G) V 1.3
Overview of Characteristic
Support IEEE802.11b/g/n Wireless Standards
Fully Self-Contained Serial-to-Wireless Functionality
Ultra-Low-Power for Battery Applications with Excellent Power Save Scheme
Support UART/SPI/USB/PWM/GPIO Data Communication Interface
Support Work As STA/AP/AP+STA Mode
Support Smart Link Function (APP program provide)
Support Wireless and Remote Firmware Upgrade Function
Support User-Defined Web Page Upload
Support DNS to Open Webpage
Support Internal/External Antenna Option
Single +3.3V Power Supply
Smallest Size: 23.1mm x 32.8mm x2.7mm
FCC/CE Certificated

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TABLE OF CONTENTS
LIST OF FIGURES.................................................................................................................................................5
LIST OF TABLES................................................................................................................................................... 5
HISTORY................................................................................................................................................................. 6
1. PRODUCT OVERVIEW................................................................................................................................ 7
1.1. GENERAL DESCRIPTION.......................................................................................................................7
1.1.1 DEVICE FEATURES.......................................................................................................................... 7
1.1.2 DEVICE PAREMETERS.................................................................................................................... 8
1.1.3 KEY APPLICATION............................................................................................................................ 8
1.2. HARDWARE INTRODUCTION............................................................................................................... 9
1.2.1. PINS DEFINITION............................................................................................................................. 9
1.2.2. ELECTRICAL CHARACTERISTICS.............................................................................................11
1.2.3. MECHANICAL SIZE........................................................................................................................ 11
1.2.4. ON-BOARD CHIP ANTENNA........................................................................................................ 12
1.2.5. EXTERNAL ANTENNA................................................................................................................... 13
1.2.6. EVALUATION KIT............................................................................................................................13
1.2.7. ORDER INFORMATION.................................................................................................................14
1.3. TYPICAL APPLICATION........................................................................................................................ 15
1.3.1. HARDWARE TYPICAL APPLICATION........................................................................................15
2. FUNCTIONAL DESCRIPTION................................................................................................................. 16
2.1. WIRELESS NETWORKING...................................................................................................................16
2.1.1. BASIC WIRELESS NETWORK BASED ON AP (INFRASTRUCTURE).................................17
2.1.2. WIRELESS NETWORK BASED ON AP+STA............................................................................ 17
2.2. WORK MODE : TRANSPARENT TRANSMISSION MODE............................................................. 18
2.3. UART FRAME SCHEME........................................................................................................................ 19
2.3.1. UART FREE-FRAME...................................................................................................................... 19
2.3.2. UART AUTO-FRAME...................................................................................................................... 19
2.4. ENCRYPTION.......................................................................................................................................... 19
2.5. NETWORK PROTOCOL........................................................................................................................ 20
2.6. MULTI-TCP LINK CONNECTION......................................................................................................... 20
2.7. POWER SAVE SCHEME....................................................................................................................... 21
2.8. PARAMETERS CONFIGURATION...................................................................................................... 22
2.9. FIRMWARE UPDATE............................................................................................................................. 22
2.10. GPIO FUNCTION.................................................................................................................................. 23
3. OPERATION GUIDELINE......................................................................................................................... 24
3.1. CONFIGURATION VIA WEB ACCESSING........................................................................................ 24
3.1.1. OPEN WEB MANAGEMENT INTERFACE................................................................................. 24
3.1.2. SYSTEM PAGE................................................................................................................................25

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3.1.3. WORK MODE PAGE.......................................................................................................................25
3.1.4. STA SETTING PAGE...................................................................................................................... 26
3.1.5. AP SETTING PAGE........................................................................................................................ 26
3.1.6. OTHER SETTING PAGE................................................................................................................27
3.1.7. ACCOUNT MANAGEMENT PAGE...............................................................................................27
3.1.8. UPGRADE SOFTWARE PAGE.....................................................................................................28
3.1.9. RESTART PAGE............................................................................................................................. 28
3.1.10. RESTORE PAGE...........................................................................................................................29
3.2. USR-WIFI232-G USAGE INTRODUCTION........................................................................................ 29
3.2.1. SOFTWARE DEBUG TOOLS........................................................................................................29
3.2.2. NETWORK CONNECTION............................................................................................................ 30
3.2.3. DEFAULT PARAMETER SETTING..............................................................................................30
3.2.4. MODULE DEBUG............................................................................................................................ 30
3.3. TYPICAL APPLICATION EXAMPLES................................................................................................. 32
3.3.1. WIRELESS CONTROL APPLICATION........................................................................................32
3.3.2. REMOTE MANAGEMENT APPLICATION.................................................................................. 32
3.3.3. TRANSPARENT SERIAL PORT APPLICATION........................................................................32
4. AT+INSTRUCTION INTRODUCTION................................................................................................... 33
4.1. CONFIGURATION MODE..................................................................................................................... 33
4.1.1. SWITCH TO CONFIGURATION MODE...................................................................................... 33
4.2. AT+ INSTRUCTION SET OVERVIEW.................................................................................................34
4.2.1. INSTRUCTION SYNTAX FORMAT.............................................................................................. 35
4.2.2. AT+ INSTRUCTION SET................................................................................................................36
4.2.2.1. AT+E...............................................................................................................................................37
4.2.2.2. AT+WMODE..................................................................................................................................37
4.2.2.3. AT+ENTM...................................................................................................................................... 37
4.2.2.4. AT+TMODE................................................................................................................................... 38
4.2.2.5. AT+MID.......................................................................................................................................... 38
4.2.2.6. AT+VER......................................................................................................................................... 38
4.2.2.7. AT+RELD....................................................................................................................................... 38
4.2.2.8. AT+Z............................................................................................................................................... 38
4.2.2.9. AT+H...............................................................................................................................................39
4.2.2.10. AT+CFGRD................................................................................................................................. 39
4.2.2.11. AT+CFGWR................................................................................................................................ 39
4.2.2.12. AT+CFGFR..................................................................................................................................39
4.2.2.13. AT+CFGTF.................................................................................................................................. 39
4.2.2.14. AT+UART.................................................................................................................................... 40
4.2.2.15. AT+ UARTF................................................................................................................................. 40
4.2.2.16. AT+ UARTFT.............................................................................................................................. 41
4.2.2.17. AT+ UARTFL...............................................................................................................................41
4.2.2.18. AT+ UARTTE.............................................................................................................................. 41
4.2.2.19. AT+ SEND................................................................................................................................... 41
4.2.2.20. AT+ RECV................................................................................................................................... 42
4.2.2.21. AT+ PING.................................................................................................................................... 42

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4.2.2.22. AT+NETP.....................................................................................................................................42
4.2.2.23. AT+ TCPLK................................................................................................................................. 43
4.2.2.24. AT+ TCPTO.................................................................................................................................43
4.2.2.25. AT+TCPDIS.................................................................................................................................43
4.2.2.26. AT+WSSSID................................................................................................................................43
4.2.2.27. AT+WSKEY................................................................................................................................. 44
4.2.2.28. AT+ WANN.................................................................................................................................. 44
4.2.2.29. AT+ WSMAC............................................................................................................................... 45
4.2.2.30. AT+ WSLK................................................................................................................................... 45
4.2.2.31. AT+ WSLQ.................................................................................................................................. 45
4.2.2.32. AT+WSCAN................................................................................................................................ 45
4.2.2.33. AT+ WSDNS............................................................................................................................... 46
4.2.2.34. AT+ LANN....................................................................................................................................46
4.2.2.35. AT+WAP...................................................................................................................................... 46
4.2.2.36. AT+WAKEY................................................................................................................................. 47
4.2.2.37. AT+WAMAC................................................................................................................................ 47
4.2.2.38. AT+WADHCP..............................................................................................................................47
4.2.2.39. AT+WADMN................................................................................................................................ 48
4.2.2.40. AT+WEBSWITCH...................................................................................................................... 48
4.2.2.41. AT+PLANG..................................................................................................................................48
4.2.2.42. AT+UPURL..................................................................................................................................49
4.2.2.43. AT+UPFILE................................................................................................................................. 49
4.2.2.44. AT+UPST.....................................................................................................................................49
4.2.2.45. AT+WEBU................................................................................................................................... 49
4.2.2.46. AT+MSLP.................................................................................................................................... 50
4.2.2.47. AT+WRMID................................................................................................................................. 50
4.2.2.48. AT+ASWD................................................................................................................................... 50
5. PACKAGE INFORMATION....................................................................................................................... 51
5.1. RECOMMENDED REFLOW PROFILE............................................................................................... 51
5.2. DEVICE HANDLING INSTRUCTION (MODULE IC SMT PREPARATION)..................................51
5.3. SHIPPING INFORMATION.................................................................................................................... 52
APPENDIX A: HW REFERENCE DESIGN............................................................................................... 53
APPENDIX B: GPIO/PWM FUNCTION......................................................................................................54
B.1 NETWORK COMMAND.......................................................................................................................... 54
B.2 HEX NETWORK COMMAND................................................................................................................. 56
APPENDIX C: CONTACT INFORMATION............................................................................................... 59

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LIST OF FIGURES
Figure 1. USR-WIFI232-G Demo..................................................................................................................9
Figure 2. USR-WIFI232-G Pins Map............................................................................................................9
Figure 3. USR-WIFI232-G Mechanical Dimension.................................................................................. 11
Figure 4. USR-WIFI232-G PCB Symbol Size...........................................................................................12
Figure 5. Suggested Module Placement Region..................................................................................... 12
Figure 6. USR-WIFI232-G Evaluation Kit..................................................................................................13
Figure 7. USR-WIFI232-G Order Information........................................................................................... 14
Figure 8. USR-WIFI232-G Hardware Typical Application...................................................................... 15
Figure 9. USR-WIFI232-G Basic Wireless Network Structure............................................................... 17
Figure 10. HF-A11 AP+STA Network Structure......................................................................................... 17
Figure 11. Multi-TCP Link Data Transmition Structure............................................................................. 21
Figure 12. Open Web Management page................................................................................................... 25
Figure 13. System Web Page....................................................................................................................... 25
Figure 14. Work Mode Page..........................................................................................................................26
Figure 15. STA Setting Page.........................................................................................................................26
Figure 16. AP Setting Page........................................................................................................................... 27
Figure 17. Other Setting Page.......................................................................................................................27
Figure 18. Account Page................................................................................................................................28
Figure 19. Upgrade SW page........................................................................................................................28
Figure 20. Restart Page................................................................................................................................. 29
Figure 21. Restore Page................................................................................................................................ 29
Figure 22. STA Interface Debug Connection.............................................................................................. 30
Figure 23. AP Interface Debug Connection................................................................................................ 30
Figure 24. “CommTools” Serial Debug Tools............................................................................................. 31
Figure 25. “TCPUDPDbg” Tools Create Connection.................................................................................31
Figure 26. “TCPUDPDbg” Tools Setting......................................................................................................31
Figure 27. “TCPUDPDbg” Tools Connection.............................................................................................. 31
Figure 28. Wireless Control Application...................................................................................................... 32
Figure 29. Remote Management Application............................................................................................. 32
Figure 30. Transparent Serial Port Application...........................................................................................33
Figure 31. USR-WIFI232-G Default UART Port Parameters................................................................... 33
Figure 32. Switch to Configuration Mode.................................................................................................... 34
Figure 33. ”AT+H” Instruction for Help......................................................................................................... 34
Figure 34. Reflow Soldering Profile..............................................................................................................51
Figure 35. Shipping Information.................................................................................................................... 52
LIST OF TABLES
Table 1 USR-WIFI232-G Module Technical Specifications.........................................................................8
Table 2 USR-WIFI232-G Pins Definition........................................................................................................ 9
Table 3 USR-WIFI232-G External Antenna Parameters........................................................................... 13

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Table 4 USR-WIFI232-G Evaluation Kit Interface Description................................................................. 14
Table 5 USR-WIFI232-G IP Stack Features................................................................................................ 20
Table 6 Standby Mode Status and Wake Up................................................................................................21
Table 7 USR-WIFI232-G GPIO Pin Mapping Table................................................................................... 23
Table 8 USR-WIFI232-G Web Access Default Setting.............................................................................. 24
Table 9 Error Code Describtion..................................................................................................................... 35
Table 10 AT+ Instruction Set List.................................................................................................................. 36
Table 11 Reflow Soldering Parameter............................................................................................................51
HISTORY
Ed. V1.0 Created on 1-29-2013.
Ed. V1.1 02-24-2013. Update AT command contents.
Ed. V1.2 03-28-2013. Update AT command contents.
Ed. V1.3 07-19-2013. Update GPIO/PWM function

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1. PRODUCT OVERVIEW
1.1. General Description
The USR-WIFI232-G is a fully self-contained small form-factor, single stream, 802.11b/g/n Wi-Fi
module, which provide a wireless interface to any equipment with a Serial/SPI/USB interface for data
transfer.USR-WIFI232-G integrate MAC, baseband processor, RF transceiver with power amplifier in
hardware and all Wi-Fi protocol and configuration functionality and networking stack, in embedded
firmware to make a fully self-contained 802.11b/g/n Wi-Fi solution for a variety of applications.
USR-WIFI232-G support AP+STA wireless networking and support Wi-Fi Direct. USR-WIFI232-G also
provides wireless and remote firmware upgrade, which satisfied all kinds of application requirement.
USR-WIFI232-G support user defined Web page and can revise the data communication protocol,
which reduce much customer’s software development and customization work.
The USR-WIFI232-G employs the world's lowest power consumption embedded architecture. It has
been optimized for all kinds of client applications in the home automation, smart grid, handheld device,
personal medical application and industrial control that have lower data rates, and transmit or receive
data on an infrequent basis.
The USR-WIFI232-G integrates all Wi-Fi functionality into a low-profile, 23.1x32.8x 2.7mm SMT
module package that can be easily mounted on main PCB with application specific circuits. Also,
module provides built-in antenna, external antenna option.
1.1.1 Device Features
Single stream Wi-Fi @ 2.4 GHz with support for WEP security mode as well as WPA/WPA2
Fully self-contained serial-to-wireless functionality.
Ultra-low-power operation with all kinds of power-save modes.
Includes all the protocol and configuration functions for Wi-Fi connectivity.
Support STA/AP/AP+STA Mode
Support Smart Link Function
Support Wireless and Remote Firmware Upgrade Function
Support User-Defined Web Page Upload
Integrated chip antenna, antenna connector options.
Compact surface mount module 23.1mm x 32.8mm x 2.7mm.
Full IPv4 and IPv6 stack.
Low power RTOS and drivers.
FCC Certified.
RoHS and CE compliant.
Single supply – 3.3V operation.

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1.1.2 Device Paremeters
Table 1 USR-WIFI232-G Module Technical Specifications
Class Item Parameters
Wireless
Parameters
Certification FCC/CE
Wireless standard 802.11 b/g/n
Frequency range 2.412GHz-2.484GHz
Transmit Power
802.11b: +17.5 dBm (@11Mbps)
802.11g: +16 dBm (@54Mbps) for CE
802.11g: +13 dBm (@54Mbps) for FCC
802.11n: +16 dBm (@HT20, MCS7) for CE
802.11n: +12 dBm (@HT20, MCS7) for FCC
Receiver Sensitivity
802.11b: -93 dBm (@11Mbps ,CCK)
802.11g: -85 dBm (@54Mbps, OFDM)
802.11n: -82 dBm (@HT20, MCS7)
Antenna Option External:I-PEX Connector
Internal:On-board PCB antenna
Hardware
Parameters
Data Interface
UART
USB, SPI, PWM…
Others: GPIO, ADC/DAC, RTC…
Operating Voltage 3.1~3.6V
Operating Current
Peak [Continuous TX]: ~200mA
Normal [WiFi ON/OFF, DTIM=100ms]:
Average. ~8mA, Peak: 200mA
Standby [WiFi Shutdown]: <80uA
Operating Temp. -40℃- 85℃
Storage Temp. -45℃- 125℃
Dimensions and Size 23.1mm×32.8mm×2.7mm
Software
Parameters
Network Type STA /AP/STA+AP
Security Mechanisms WEP/WPA-PSK/WPA2-PSK
Encryption WEP64/WEP128/TKIP/AES
Update Firmware Local Wireless, Remote
Customization Web Page Upgrade
Support SDK for application develop
Serial command AT+instruction set
Network Protocol IPv4, IPv6,TCP/UDP/FTP/HTTP
User Configuration AT+instruction set. Android/ iOS
Smart Link APP tools
1.1.3 Key Application
Remote equipment monitoring
Asset tracking and telemetry
Security
Industrial sensors and controls
Home automation
Medical devices

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1.2. Hardware Introduction
Figure 1. USR-WIFI232-G Demo
1.2.1. Pins Definition
Figure 2. USR-WIFI232-G Pins Map
Table 2 USR-WIFI232-G Pins Definition
Pin Describtion Net Name Signal Type Comments
1,17,32,48 Ground GND Power
2 JTAG Function JTAG_TCK I, PU JTAG/Debug functional pin,
No connect if not use.
3 JTAG Function JTAG_TDO O
4 JTAG Function JTAG_TDI I,PU
5 JTAG Function JTAG_TMS I,PU
6 N.C No connect

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7 RTC Input 1 ALARM1 I.PU GPIO7, Sleep_RQ Pin
(Suggest 100K ohm Pull up even
not use this function.)
8 RTC Output 1 RTC_OUT1 O GPIO8, Sleep_ON Pin
9 +3.3V Power DVDD Power
10 N.C No connect
11 A/D Input 1 ADC1 I/O,PD GPIO11, No connect if not use.
12 A/D Input 2 ADC2 I/O,PD GPIO12, No connect if not use.
13 RTC Input 2 ALARM2 I,PD GPIO13, No connect if not use.
14 N.C No connect
15 N.C No link, Must No connect
16 PWM 1 Output USB_PIO I/O GPIO16, No connect if not use.
18 N.C No connect
19 N.C No connect
20 PWM 2 Output GPIO20 I/O GPIO20, No connect if not use.
21 USB Interface USB- I/O 90 ohm Diff. Line
22 USB Interface USB+ I/O 90 ohm Diff. Line
23 GPIO 1 Output PWMH0 O GPIO23, No connect if not use.
24 PWM Output0-low PWML0 O GPIO24, No connect if not use.
25 N.C No connect
26 GPIO 0 Output GPIO26 I/O GPIO26, No connect if not use.
27 SPI Interface SPI_MISO I/O, PU No connect if not use.
28 SPI Interface SPI_CLK I/O, PU No connect if not use.
29 SPI Interface SPI_CS I/O,PU No connect if not use.
30 SPI Interface SPI_MOSI I/O.PD No connect if not use.
31 +3.3V Power DVDD Power
33 N.C No connect
34 +3.3 Power DVDD Power
35 GPIO GPIO35 I/O,PD GPIO35, WPS functional pin
36 N.C No connect
37 N.C No connect
38 N.C No connect
39 UART0 UART0_TX I,PU UART Communication Pin
40 UART0 UART0_RTS 0 UART Communication Pin
41 UART0 UART0_RX 0 UART Communication Pin
42 UART0 UART0_CTS I,PU UART Pin (Or RS485 Control)
43 Wi-Fi Status nLink O,PU “0”- Wi-Fi Linked
“1”- No WIFI Linked
No connect if not use.
44 Module Boot Up
Indicator
nReady O,PU “0” – Boot-up OK;
“1” – Boot-up No OK;
No connect if not use.;
45 Restore
Configuration
nReload I,PU Module will restore factory
default after set this pin “0” more
than 1s, then set “1”.
(Suggest 50K ohm Pull up even
not use this function.)
46 GPIO 2 Output PWMFI0 I/O GPIO46, No connect if not use.

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47 Module Reset EXT_RESETn I,PU “Low” effective reset input.
1.2.2. Electrical Characteristics
Absolute Maximum Ratings:
Parameter Condition Min. Typ. Max. Unit
Storage temperature range -45 125 °C
Maximum soldering temperature IPC/JEDEC J-STD-020 260 °C
Supply voltage 0 3.8 V
Voltage on any I/O pin 0 3.3 V
ESD (Human Body Model HBM) TAMB=25°C 2 KV
ESD (Charged Device Model, CDM) TAMB=25°C 1 KV
Power Supply & Power Consumption:
Parameter Condition Min. Typ. Max. Unit
Operating Supply voltage 3.1 3.3 3.8 V
Supply current, peak Continuous Tx 200 mA
Supply current, IEEE PS DTIM=100ms 5 mA
Output high voltage Sourcing 6mA 2.8 V
Output low voltage Sinking 6mA 0.2 V
Input high voltage 2.2 V
Input low voltage 0.8 V
Input leakage current +/-25 nA
Analog input range 0 3 V
Analog output range 0 3 V
1.2.3. Mechanical Size
USR-WIFI232-G modules physical size （Unit: mm）as follows:
Figure 3. USR-WIFI232-G Mechanical Dimension
USR-WIFI232-G Module PCB symbol size (mm) as follows:

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Figure 4. USR-WIFI232-G PCB Symbol Size
1.2.4. On-board Chip Antenna
USR-WIFI232-G module support internal on-board chip antenna option. When customer select internal
antenna, you shall comply with following antenna design rules and module location suggestions:
For customer PCB, RED color region (8.3x18.4mm) can’t put componet or paste GND net;
Antenna must away from metal or high components at least 10mm;
Antenna can’t be shielded by any meal enclosure; All cover, include plastic, shall away from
antenna at least 10mm;
Figure 5. Suggested Module Placement Region
USR company suggest USR-WIFI232-G module better locate in following region at customer board,
which to reduce the effect to antenna and wireless signal, and better consult USR company technical
people when you structure your module placement and PCB layout.

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1.2.5. External Antenna
USR-WIFI232-G module supports internal antenna and external antenna option for user dedicated
application.
If user select external antenna, USR-WIFI232-G modules must be connected to the 2.4G antenna
according to IEEE 802.11b/g/n standards.
The antenna parameters required as follows:
Table 3 USR-WIFI232-G External Antenna Parameters
1.2.6. Evaluation Kit
USR company provides the evaluation kit to promote user to familiar the product and develop the
detailed application. The evaluation kit shown as below, user can connect to USR-WIFI232-G module
with the RS-232 UART, RS485, USB (Internal UART-USB convetor) or Wireless port to configure the
parameters, manage the module or do the some functional tests.
Figure 6. USR-WIFI232-G Evaluation Kit
Notes: User need download USB - UART port driver from USR company web or contact with technical
support people for more detail.
The external interface description for evaluation kit as follows:
Item Parameters
Frequency range 2.4~2.5GHz
Impedance 50 Ohm
VSWR 2 (Max)
Return Loss -10dB (Max)
Connector Type I-PEX or populate directly

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Table 4 USR-WIFI232-G Evaluation Kit Interface Description
1.2.7. Order Information
Base on customer detailed requirement, USR-WIFI232-G series modules provide different variants
and physical type for detailed application.
Figure 7. USR-WIFI232-G Order Information
Function Name Description
External
Interface
COM1 Main data/command RS-232 interface
RS485 Main data/command RS-485 interface
JTAG JTAG data debug interface (Not for user use)
USB2TTL UART to USB debug interface. (For PC without
RS232, need load driver). Can be Power input.
USB DEBUG USB2.0 data interface.
DC Jack DC jack for power in, 5~18V input.
DC5-18V DC jack for power in, 5~18V input.
BAT 2 Li-Battery Power Supply.
EXT PORT USR-WIFI232-G GPIO function extend interface
connector
JMP1,JMP2 Reserved, No Jumper required.
JMP3 4Pin USB or RS232 Jumper. Left jump select USB.
JMP6 3Pin RS485 Jumper. No jump selects RS232.
LED Power 3.3V Power Indicator
nLink nLink -WiFi LINK Indicator
nReady
nReady – Module Boot up Ready Indicator
On (“low”)- Module boot up OK;
Off (“high”)- Module bot up failed;
Twinkle- Remote Upgrade Ongoing;
Sleep_ON
Sleep_ON-Module asleep or awake Indicator
On (“low”)- Module in shundown(deep sleep) status;
Off (“high”)- Module in normal status;
Twinkle- Boot loader Upgrade Ongoing;
Button nReset Used to reset the module.
nReload Restore factory default configuration after push this
pin more than 3s.
WPS WPS Button （Reserved, No Use）
Sleep_RQ Pin Sleep Control button, more than 1s to put
module in standby mode.

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1.3. Typical Application
1.3.1. Hardware Typical Application
Figure 8. USR-WIFI232-G Hardware Typical Application
Notes：
nReset- Module hardware reset signal. Input. Logics “0” effective.
There is pull-up resister internal and no external pull-up required. When module power up or some
issue happened, MCU need assert nRST signal “0” at least 10ms, then set” 1” to keep module fully
reset.
nLink- Module WIFI connection status indication. Output.
When module connects to AP (AP associated), this pin will output “0”. This signal used to judge if
module already at WiFi connection status. Thers is pull-up resister internal and no external pull-up
required. If n Link function not required, can leave this pin open.
nReady- Module boot up ready signal. Output. Logics “0” effective.
The module will output “0” after normal boot up. This signal used to judge if module finish boot up and
ready for application or working at normal mode. If nReady function not required, can leave this pin
open.
nReload- Module restore to factory default configuration.Input. Logics “0” effective.
User can de-assert nReload signal “0” more than 3s through button or MCU pin, then release, module
will restore to factory default configuration and re-start boot up process.. If nReload function not
required, we still suggest 50K~100K ohm pull up added outside the module.
Sleep-RQ- Module Pin Sleep Control. Input.

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The user should de-assert this pin low “0”, after 1’s assert to high ”1” to put the module to sleep status.
Also at the deep sleep/standby mode, user can de-assert this pin low “0”, after 1’s assert to high ”1” to
put the module to wake up the module. If Sleep_RQ function not required, We still suggest 50K~100K
ohm pull up added outside the module.
Sleep-ON- Module Pin Sleep Indicator. Output.
This pin is used to indicate that the module is asleep (Module output “0”) or awake (Module output “1”)
status. If user doesn't use pin sleep function, can leave this pin open.
UART0_TXD/RXD- UART port data transmit and receive signal.
2. FUNCTIONAL DESCRIPTION
2.1. Wireless Networking
USR-WIFI232-G module can be configured as both wireless STA and AP base on network type.
Logically there are two interfaces in USR-WIFI232-G. One is for STA, and another is for AP. When

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USR-WIFI232-G works as AP, other STA equipments are able to connect to wireless LAN via USR-
WIFI232-G module. Wireless Networking with USR-WIFI232-G is very flexible.
Notes:
AP: that is the wireless Access Point, the founder of a wireless network and the centre of the network
nodes. The wireless router we use at home or in office may be an AP.
STA: short for Station, each terminal connects to a wireless network (such as laptops, PDA and other
networking devices) can be called with a STA device.
2.1.1. Basic Wireless Network Based On AP (Infrastructure)
Infrastructure: it’s also called basic network. It built by AP and many STAs which join in.
The characters of network of this type are that AP is the centre, and all communication between STAs
is transmitted through the AP. The figure following shows such type of networking.
Figure 9. USR-WIFI232-G Basic Wireless Network Structure
2.1.2. Wireless Network Based On AP+STA
USR-WIFI232-G module support AP+STA network mode, means module support one AP interface
and one STA interface at the same time, as following figure,
Figure 10.HF-A11 AP+STA Network Structure

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When module enables AP+STA function, Module’s STA interface can connect with router and connect
to TCP server in the network. At the same time, module’s AP interface is also active and permit
phone/PAD to connect through TCPB, then phone/PAD can control user device and and setting the
module parameters,
The advantage of AP+STA mode is:
Users can easily setting and track user device through Phone/PAD and not change the
orginal network setting.
Users can easily setting module’s parameters through WiFi when module works as STA
mode.
2.2. Work Mode : Transparent Transmission Mode
USR-WIFI232-G module support serial interface transparent transmission mode. The benefit of this
mode is achieves a plug and play serial data port, and reduces user complexity furthest. In this mode,
user should only configure the necessary parameters. After power on, module can automatically
connect to the default wireless network and server.
As in this mode, the module's serial port always work in the transparent transmission mode, so users
only need to think of it as a virtual serial cable, and send and receive data as using a simple serial. In
other words, the serial cable of users’ original serial devices is directly replaced with the module; user
devices can be easy for wireless data transmission without any changes.
The transparent transmission mode can fully compatible with user’s original software platform and
reduce the software development effort for integrate wireless data transmission.
The parameters which need to configure include:
Wireless Network Parameters
Wireless Network Name（SSID）
Security Mode
Encryption Key
TCP/UDP Linking Parameters
Protocol Type
Link Type（Server or Client）
Target Port ID Number
Target Port IP Address
Serial Port Parameters
Baud Rate
Data Bit
Parity (Check) Bit
Stop Bit
Hardware Flow Control

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2.3. UART Frame Scheme
2.3.1. UART Free-Frame
USR-WIFI232-G support UART free-frame function. If user select open this function, module will check
the intervals between any two bytes when reciving UART data. If this interval time exceeds defined
value (50ms default), USR-WIFI232-G will think it as the end of one frame and transfer this free-frame
to WiFi port, or USR-WIFI232-G will receive UART data untill 1400 bytes, then transfer 1400 bytes
frame to WiFi port.
USR-WIFI232-G’s default interval time is 50ms. User can also set this interval to fast (10ms) through
AT command. But user have to consider if user MCU can send UART data with 10ms interval ,or the
UART data may be divide as fragment.
Through AT command: AT+UARTTE=fash/normal, user can set the interval time: fast (10ms) and
normal (50ms).
2.3.2. UART Auto-Frame
USR-WIFI232-G support UART auto-frame function. If user select open this function and setting auto-
frame trigger length and auto-frame trigger time parameters, then module will auto framing the data
which received from UART port and transmitting to the network as pre-defined data structure.
Auto-frame trigger length: The fixed data length that module used to transmitting to the
network.
Auto-frame trigger time: After the trigger time, if UART port received data can’t reach auto-
frame trigger length, then module will transmitting available data to the network and bypass
the auto-frame trigger length condition.
Detailed UART auto-frame function can refer to AT+ instruction set “UARTF/UARTFT/UARTFL”
introduction.
2.4. Encryption
Encryption is a method of scrambling a message that makes it unreadable to unwanted parties, adding
a degree of secure communications. There are different protocols for providing encryption, and the
USR-WIFI232-G module supports following:
WEP
WPA-PSK/TKIP
WPA-PSK/AES
WPA2-PSK/TKIP
WPA2-PSK/AES

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2.5. Network Protocol
USR-WIFI232-G includes a fully IPv4 and IPv6 capable stack supporting TCP and UDP
connection.Following table shows the key features of the USR-WIFI232-G module IP stack, which
including support for DHCP, multicast, and ARP.
The Frame size limits are (including IP headers):
Tranmit
TCP/UDP/ICMP (v4): 1576
ICMP (v6): 1576
UCP/UDP (v6): 1220
Receive
TCP/UDP (v4): 1516
TCP/UDP (v6): 1496
ICMPv4 and ICMPv6: 5000
Table 5 USR-WIFI232-G IP Stack Features
2.6. Multi-
TCP
Link
Connection
When USR-WIFI232-G module configured as TCP Server, it supports Multi-TCP link connection, and
maximum eight TCP clients permit to connect to USR-WIFI232-G module. User can realize multi-TCP
link connection at each work mode.
Multi-TCP link connection will work as following structure:
Upstream:
All dates from different TCP connection or client will be transmitted to the serial port as a sequence.
Downstream:
All data from serial port (user) will be duplicate and broadcast to every TCP connection or client.
Detailed multi-TCP link data transmition structure as following figure:
Feature Support
ARP Supported
Forwarding Supported
Fragmentation/Reassembly Planned
IPv4/v6 Header Processing Supported
UDP/TCP Socket Support Supported
DHCP v4 Supported
Neighbor Discovery Supported
Broadcast/Multicast Supported
Path MTU Discovery Supported
Address Auto-Configuration Supported
Multicast Planned
TCP Zero Copy Feature Supported