USR IOT USR-WIFI232-T User manual

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Low Power WiFi Module User Manual
V 1.3
Overview of Characteristic
Support IEEE802.11b/g/n Wireless Standards
Based on Self-developed High Cost Effective MCU
Ultra-Low-Power for Battery Applications with Excellent Power Save
Scheme
Support UART/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 WPS Function
Support Multi-TCP Link (5 Channel) Apllication
Support Dial Switch Power Control
Support External IPEX or Pad Interface Antenna Option
Single +3.3V Power Supply
Smallest Size: 22mm x 13.5mm x 6mm, 1x10 2mm Connector
FCC/CE Certificated

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TABLE OF CONTENTS
LIST OF FIGURES...............................................................................................................................................6
LIST OF TABLES................................................................................................................................................. 7
HISTORY..................................................................................................................................................................8
1. PRODUCT OVERVIEW................................................................................................................................. 9
1.1. GENERAL DESCRIPTION.................................................................................................................... 9
1.1.1 DEVICE FEATURES....................................................................................................................... 9
1.1.2 DEVICE PARAMETERS................................................................................................................10
1.1.3 KEY APPLICATION.....................................................................................................................10
1.2. HARDWARE INTRODUCTION............................................................................................................. 12
1.2.1. PINS DEFINITION.................................................................................................................. 12
1.2.2. ELECTRICAL CHARACTERISTICS........................................................................................13
1.2.3. MECHANICAL SIZE.................................................................................................................. 14
1.2.4. EXTERNAL ANTENNA................................................................................................................15
1.2.5. EVALUATION KIT.....................................................................................................................15
1.3. TYPICAL APPLICATION.................................................................................................................. 16
1.3.1. HARDWARE TYPICAL APPLICATION................................................................................... 16
1.3.2. SMART LED APPLICATION HARDWARE TYPICAL CONNECTION.............................. 17
2. FUNCTIONAL DESCRIPTION............................................................................................................... 19
2.1. WIRELESS NETWORKING.................................................................................................................. 19
2.1.1. BASIC WIRELESS NETWORK BASED ON AP (INFRASTRUCTURE)............................19
2.1.2. WIRELESS NETWORK BASED ON AP+STA......................................................................... 19
2.2. WORK MODE : TRANSPARENT TRANSMISSION MODE............................................................. 20
2.3. UART FRAME SCHEME.......................................................................................................................21
2.3.1. UART FREE-FRAME.................................................................................................................. 21
2.3.2. UART AUTO-FRAME.................................................................................................................. 22
2.4. ENCRYPTION........................................................................................................................................22
2.5. PARAMETERS CONFIGURATION...................................................................................................... 22
2.6. FIRMWARE UPDATE............................................................................................................................23
2.7. GPIO/PWM FUNCTION.......................................................................................................................24
2.8. SOCKET B FUNCTION.......................................................................................................................25
2.9. MULTI-TCP LINK CONNECTION....................................................................................................25
3. OPERATION GUIDELINE....................................................................................................................... 27
3.1. CONFIGURATION VIA WEB ACCESSING..................................................................................... 27
3.1.1. OPEN WEB MANAGEMENT INTERFACE.................................................................................27
3.1.2. SYSTEM PAGE............................................................................................................................28
3.1.3. WORK MODE PAGE.....................................................................................................................28
3.1.4. STA SETTING PAGE................................................................................................................29
3.1.5. AP SETTING PAGE.................................................................................................................. 29
3.1.6. OTHER SETTING PAGE........................................................................................................... 30
3.1.7. ACCOUNT MANAGEMENT PAGE............................................................................................... 31

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3.1.8. UPGRADE SOFTWARE PAGE....................................................................................................31
3.1.9. RESTART PAGE......................................................................................................................... 31
3.1.10. RESTORE PAGE....................................................................................................................... 32
3.2. USR-WIFI232-T USAGE INTRODUCTION...................................................................................33
3.2.1. SOFTWARE DEBUG TOOLS...................................................................................................... 33
3.2.2. NETWORK CONNECTION........................................................................................................... 33
3.2.3. DEFAULT PARAMETER SETTING.......................................................................................... 33
3.2.4. MODULE DEBUG......................................................................................................................... 34
3.3. TYPICAL APPLICATION EXAMPLES............................................................................................ 35
3.3.1. WIRELESS CONTROL APPLICATION................................................................................... 35
3.3.2. REMOTE MANAGEMENT APPLICATION.................................................................................36
3.3.3. TRANSPARENT SERIAL PORT APPLICATION.................................................................. 36
4. AT+INSTRUCTION INTRODUCTION.................................................................................................. 37
4.1. CONFIGURATION MODE.................................................................................................................... 37
4.1.1. SWITCH TO CONFIGURATION MODE................................................................................... 37
4.2. AT+ INSTRUCTION SET OVERVIEW............................................................................................ 38
4.2.1. INSTRUCTION SYNTAX FORMAT.......................................................................................... 38
4.2.2. AT+ INSTRUCTION SET.........................................................................................................39
4.2.2.1. AT+E........................................................................................................................................41
4.2.2.2. AT+WMODE.............................................................................................................................. 41
4.2.2.3. AT+ENTM.................................................................................................................................42
4.2.2.4. AT+TMODE.............................................................................................................................. 42
4.2.2.5. AT+MID................................................................................................................................... 42
4.2.2.6. AT+VER................................................................................................................................... 42
4.2.2.7. AT+RELD.................................................................................................................................43
4.2.2.8. AT+FCLR.................................................................................................................................43
4.2.2.9. AT+Z........................................................................................................................................43
4.2.2.10. AT+H..................................................................................................................................... 43
4.2.2.11. AT+CFGRD............................................................................................................................43
4.2.2.12. AT+CFGWR............................................................................................................................43
4.2.2.13. AT+CFGFR............................................................................................................................44
4.2.2.14. AT+CFGTF............................................................................................................................44
4.2.2.15. AT+UART.............................................................................................................................. 44
4.2.2.16. AT+ UARTF......................................................................................................................... 45
4.2.2.17. AT+ UARTFT....................................................................................................................... 45
4.2.2.18. AT+ UARTFL....................................................................................................................... 45
4.2.2.19. AT+ UARTTE....................................................................................................................... 46
4.2.2.20. AT+ SEND............................................................................................................................46
4.2.2.21. AT+ RECV............................................................................................................................46
4.2.2.22. AT+ PING............................................................................................................................46
4.2.2.23. AT+NETP.............................................................................................................................. 47
4.2.2.24. AT+ MAXSK......................................................................................................................... 47
4.2.2.25. AT+ TCPLK......................................................................................................................... 48
4.2.2.26. AT+ TCPTO......................................................................................................................... 48

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4.2.2.27. AT+TCPDIS......................................................................................................................... 48
4.2.2.28. AT+SOCKB............................................................................................................................49
4.2.2.29. AT+TCPDISB....................................................................................................................... 49
4.2.2.30. AT+TCPTOB......................................................................................................................... 49
4.2.2.31. AT+TCPLKB......................................................................................................................... 50
4.2.2.32. AT+SNDB.............................................................................................................................. 50
4.2.2.33. AT+RCVB.............................................................................................................................. 50
4.2.2.34. AT+WSSSID......................................................................................................................... 50
4.2.2.35. AT+WSKEY............................................................................................................................51
4.2.2.36. AT+ WANN............................................................................................................................51
4.2.2.37. AT+ WSMAC......................................................................................................................... 52
4.2.2.38. AT+ WSLK............................................................................................................................52
4.2.2.39. AT+ WSLQ............................................................................................................................52
4.2.2.40. AT+WSCAN............................................................................................................................52
4.2.2.41. AT+ WSDNS......................................................................................................................... 53
4.2.2.42. AT+ LANN............................................................................................................................53
4.2.2.43. AT+WAP.................................................................................................................................53
4.2.2.44. AT+WAKEY............................................................................................................................54
4.2.2.45. AT+WAMAC............................................................................................................................54
4.2.2.46. AT+WADHCP......................................................................................................................... 54
4.2.2.47. AT+WADMN............................................................................................................................55
4.2.2.48. AT+PLANG............................................................................................................................55
4.2.2.49. AT+UPURL............................................................................................................................55
4.2.2.50. AT+UPFILE......................................................................................................................... 56
4.2.2.51. AT+UPWEB............................................................................................................................56
4.2.2.52. AT+UPCFG............................................................................................................................56
4.2.2.53. AT+UPNVR............................................................................................................................56
4.2.2.54. AT+UPAUTO......................................................................................................................... 57
4.2.2.55. AT+LOGSW............................................................................................................................57
4.2.2.56. AT+LOGPORT....................................................................................................................... 57
4.2.2.57. AT+UPST.............................................................................................................................. 58
4.2.2.58. AT+WEBU.............................................................................................................................. 58
4.2.2.59. AT+MSLP.............................................................................................................................. 58
4.2.2.60. AT+NTPRF............................................................................................................................58
4.2.2.61. AT+NTPEN............................................................................................................................59
4.2.2.62. AT+NTPTM............................................................................................................................59
4.2.2.63. AT+WRMID............................................................................................................................59
4.2.2.64. AT+RLDEN............................................................................................................................59
4.2.2.65. AT+ASWD.............................................................................................................................. 60
4.2.2.66. AT+MDCH.............................................................................................................................. 60
4.2.2.67. AT+TXPWR............................................................................................................................60
4.2.2.68. AT+LPTIO............................................................................................................................61
5. PACKAGE INFORMATION....................................................................................................................... 62
5.1. RECOMMENDED REFLOW PROFILE................................................................................................. 62

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5.2. DEVICE HANDLING INSTRUCTION (MODULE IC SMT PREPARATION)............................62
5.3. SHIPPING INFORMATION................................................................................................................63
APPENDIX A: HW REFERENCE DESIGN................................................................................................64
APPENDIX B: CONTROL GPIO/PWM FUNCTION WITH NETWORK COMMANDS.......................66
B.1 NETWORK COMMAND.............................................................................................................................. 66
B.2 HEXADECIMAL NETWORK COMMAND...............................................................................................69
APPENDIX C: HTTP PROTOCOL TRANSFER........................................................................................71
C.1. HTTP AT COMMAND............................................................................................................................71
C.1.1. AT+ HTTPURL............................................................................................................................71
C.1.2. AT+ HTTPTP.............................................................................................................................. 71
C.1.3. AT+ HTTPPH.............................................................................................................................. 71
C.1.4. AT+ HTTPCN.............................................................................................................................. 72
C.1.5. AT+ HTTPUA.............................................................................................................................. 72
C.1.6. AT+ HTTPDT.............................................................................................................................. 72
C.2. HTTP EXAMPLE...................................................................................................................................72
APPENDIX D: CONTACT INFORMATION................................................................................................74

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LIST OF FIGURES
Figure 1. USR-WIFI232-T Pins Map................................................................................................... 13
Figure 2. USR-WIFI232-T Mechanical Dimension.......................................................................15
Figure 3. USR-WIFI232-T External Antenna picture............................................................. 16
Figure 4. USR-WIFI232-T Evaluation Kit..................................................................................... 16
Figure 5. USR-WIFI232-T Hardware Typical Application................................................... 17
Figure 6. USR-WIFI232-T Smart LED Application Hardware Connection.................... 18
Figure 7. USR-WIFI232-T Basic Wireless Network Structure..........................................20
Figure 8. AP+STA Network Structure...............................................................................................21
Figure 9. Socket B function demo................................................................................................... 26
Figure 10. Multi-TCP Link Data Transmition Structure................................................... 26
Figure 11. Open Web Management page............................................................................................ 28
Figure 12. System Web Page..................................................................................................................29
Figure 13. Work Mode Page.................................................................................................................... 30
Figure 14. STA Setting Page............................................................................................................... 30
Figure 15. AP Setting Page..................................................................................................................31
Figure 16. Other Setting Page...........................................................................................................31
Figure 17. Account Page......................................................................................................................... 32
Figure 18. Upgrade SW page..................................................................................................................32
Figure 19. Restart Page......................................................................................................................... 33
Figure 20. Restore Page......................................................................................................................... 33
Figure 21. STA Interface Debug Connection..............................................................................34
Figure 22. AP Interface Debug Connection................................................................................ 34
Figure 23. “CommTools” Serial Debug Tools..............................................................................35
Figure 24. “TCPUDPDbg” Tools Create Connection..................................................................35
Figure 25. “TCPUDPDbg” Tools Setting..........................................................................................35
Figure 26. “TCPUDPDbg” Tools Connection...................................................................................36
Figure 27. Wireless Control Application...................................................................................36
Figure 28. Remote Management Application................................................................................ 37
Figure 29. Transparent Serial Port Application..................................................................37
Figure 30. USR-WIFI232-T Default UART Port Parameters................................................. 38
Figure 31. Switch to Configuration Mode...................................................................................38
Figure 32. ”AT+H” Instruction for Help..................................................................................... 39
Figure 33. Reflow Soldering Profile............................................................................................ 63

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LIST OF TABLES
Table 1 USR-WIFI232-T Module Technical Specifications....................................... 10
Table 2 USR-WIFI232-T Pins Definition..............................................................................12
Table 3 Absolute Maximum Ratings..........................................................................................13
Table 4 Power Supply & Power Consumption.......................................................................13
Table 5 USR-WIFI232-T External Antenna Parameters................................................. 15
Table 6 USR-WIFI232-T Evaluation Kit Interface Description........................... 15
Table 7 USR-WIFI232-T GPIO/PWM Pin Mapping Table................................................... 23
Table 8 USR-WIFI232-T Web Access Default Setting................................................... 25
Table 9 Error Code Describtion...............................................................................................37
Table 10 AT+ Instruction Set List..........................................................................................37
Table 11 Reflow Soldering Parameter..................................................................................... 60

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HISTORY
Ed. V1.0 08-01-2013 First Version.
Ed. V1.1 09-11-2013 Update AT command.
Ed. V1.2 10-12-2013 Update AT command. Update PWM/GPIO function. Add
HTTP protocol demo. Add auto-frame function.
Ed. V1.3 10-18-2013 Add nReload Pin wireless upgrade and config
description, add nLink Pin wireless upgrade indication description.

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1. PRODUCT OVERVIEW
1.1. General Description
The USR-WIFI232-T 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-T
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.
The USR-WIFI232-T 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-T 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
Based on Self-developed High Cost Performance MCU
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 External IPEX or Pad Interface antenna connector options.
Support Dial Switch to Control Power
Support Max 3 Channel PWM Output
Compact surface mount module 22mm x 13.5mm x 6mm
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 Parameters
Table 1 USR-WIFI232-T Module Technical Specifications
Class Item Parameters
Wireless
Parameter
s
Certification FCC/CE
Wireless standard 802.11 b/g/n
Frequency range 2.412GHz-2.484GHz
Transmit Power
802.11b: +16 +/-2dBm (@11Mbps)
802.11g: +14 +/-2dBm (@54Mbps)
802.11n: +13 +/-2dBm (@HT20,
MCS7)
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
External:Pad connector
Hardware
Parameter
s
Data Interface UART
PWM, GPIO
Operating Voltage 2.8~3.6V
Operating Current
Peak [Continuous TX]: ~200mA
Normal [WiFi ON/OFF,
DTIM=100ms]:
Average. ~12mA, Peak: 200mA
Standby [WiFi Shutdown]: <200uA
Power Down Switch: <10uA
Operating Temp. -40℃- 85℃
Storage Temp. -45℃- 125℃
Dimensions and
Size 22mm x 13.5mm x 6mm
External Interface 1x10, 2mm DIP
Software
Parameter
s
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
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

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Security
Industrial sensors and controls
Home automation
Medical devices

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1.2. Hardware Introduction
1.2.1. Pins Definition
Figure 1. USR-WIFI232-T Pins Map
Table 2 USR-WIFI232-T Pins Definition
Pin Description Net Name Signal
Type
Comments
1 Ground GND Power
2 +3.3V Power DVDD Power 3.3V@250mA
3 Restore
Configuration
nReload I,PU Detailed functions see <Notes>
4 Module Reset EXT_RESETn I,PU “Low” effective reset input.
5 UART0 UART0_RX I GPIO5, No connect if not use.
6 UART0 UART0_TX O GPIO6, No connect if not use.
7 Power Control
Switch
PWR_SW I,PU “0” – Power Down Mode(Lowest
Power Consumption)
“1” – Normal mode
8 PWM Channel 3 PWM_3 I/O Can be configured as WPS/GPIO18
No connect if not use.
9 PWM Channel 2 PWM_2 I/O Can be configured as
nReady/GPIO12.
No connect if not use.
10 PWM Channel 1 PWM_1 I/O Can be configured as
nLink/GPIO11.
Detailed functions see <Notes>
<Notes>
nReload Pin (Button) function：
1. When this pin is set to “low” during module boot up, the module will
enter wireless firmware and config upgrade mode. This mode is used
for customer manufacture.
(USR Technology will provide software tools for customer batch
configuration and upgrade firmware during mass production)

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2. After module is powered up, short press this button ( “Low” < 3s )
to make the module go into “Smart Link “ config mode, waiting for
APP to set password and other information.
3. After module is powered up, long press this button ( “Low” > 3s )
to make the module recover to factory setting.
USR Technology strongly suggest customer fan out this pin to connector
or button for “Manufacture” and “ Smart Link” application.
nLink Pin (LED) function：
1. At wireless firmware and config upgrade mode , this LED used to
indicate configure and upgrade status.
2. At “Smart Link “ config mode, this LED used to indicate APP to
finish setting.
3. At normal mode, it’s Wi-Fi link status indicator
USR Technology strongly suggest customer fan out this pin to LED.
1.2.2. Electrical Characteristics
Table 3 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
Table 4 Power Supply & Power Consumption:
Parameter Condition Min. Typ. Max. Unit
Operating Supply voltage 2.8 3.3 3.8 V
Supply current, peak Continuous Tx 200 mA
Supply current, IEEE PS DTIM=100ms 12 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

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1.2.3. Mechanical Size
USR-WIFI232-T modules physical size （Unit: mm）as follows:
Figure 2. USR-WIFI232-T Mechanical Dimension
1.2.4. External Antenna
USR-WIFI232-T supports two way of external antenna as the following
picture show, The IPEX interface or the PAD interface. The user may choose
one of them. If user select external antenna, USR-WIFI232-T modules must
be connected to the 2.4G antenna according to IEEE 802.11b/g/n standards.
The antenna parameters required as follows:
Figure 3. USR-WIFI232-T External Antenna picture

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Table 5 USR-WIFI232-T External Antenna Parameters
1.2.5. Evaluation Kit
USR Technology 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-T module with the RS-232 UART,
manage the module or do the some functional tests. The EVK support 5V DC
power supply.
Figure 4. USR-WIFI232-T Evaluation Kit
The external interface description for evaluation kit as follows:
Table 6 USR-WIFI232-T Evaluation Kit Interface
Description
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
Function Name Description
External
Interface
RS232 Main data/command RS-232 interface
DC5V DC jack for power in, 5V input.
Button nReset Used to reset the module.
nReload
Restore factory default configuration
after push this pin more than 3s.
See 1.2.1

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1.3. Typical Application
1.3.1. Hardware Typical Application
Figure 5. USR-WIFI232-T Hardware Typical Application
1.3.2. Smart LED Application Hardware Typical Connection
Figure 6. USR-WIFI232-T Smart LED Application Hardware Connection
Notes:

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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.
nReload- Module restore to factory default configuration.Input. Logics “0”
effective.
(This pin is recommend to connect to button, is used to enter wireless
upgrade mode)
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, can leave this
pin open.
UART0_TXD/RXD- UART port data transmit and receive signal.
PWM-n- PWM control signal output. It can also be configured as GPIO output.
“AT+LPTIO=on” command configure PWM_1 pin as nLink、PWM_2 pin as nReady、
PWM_3 as WPS function.
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.
(This pin is recommend to connect to LED, indicate status when the module
in wireless upgrade mode)
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 nLink
function not required, can leave this pin open.

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2. FUNCTIONAL DESCRIPTION
2.1. Wireless Networking
USR-WIFI232-T module can be configured as both wireless STA and AP base on
network type. Logically there are two interfaces in USR-WIFI232-T. One is
for STA, and another is for AP. When USR-WIFI232-T works as AP, other STA
equipments are able to connect to wireless LAN via USR-WIFI232-T module.
Wireless Networking with USR-WIFI232-T is very flexible.
Notes:
AP: that is the wireless Access Point, the founder of a wireless network
and the center 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 center, and all
communication between STAs is transmitted through the AP. The figure
following shows such type of networking.
Figure 7. USR-WIFI232-T Basic Wireless Network Structure
2.1.2. Wireless Network Based On AP+STA
USR-WIFI232-T module support AP+STA network mode, means module support one
AP interface and one STA interface at the same time, as following figure,

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Figure 8. AP+STA Network Structure
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 original 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-T 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.

Low power WIFI module user manual http://en.usr.cn
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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
2.3. UART Frame Scheme
2.3.1. UART Free-Frame
USR-WIFI232-T support UART free-frame function. If user select open this
function, module will check the intervals between any two bytes when
receiving UART data. If this interval time exceeds defined value (50ms
default), USR-WIFI232-T will think it as the end of one frame and transfer
this free-frame to WiFi port, or USR-WIFI232-T will receive UART data until
1000 bytes, then transfer 1000 bytes frame to WiFi port.
USR-WIFI232-T’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-T 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.