USR IOT USR-WIFI232-A2 User manual

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USR- WIFI232-A2 Hardware Manual
File version: 1.0.0

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Content
USR-WIFI232-A2 Hardware Manual ............................................................................................ 1
1. Product Overview ..................................................................................................................... 3
1.1. Dimension ....................................................................................................................... 3
1.2. Encapsulation .................................................................................................................. 3
1.3. Pin Defination.................................................................................................................. 4
2. Hardware Design ...................................................................................................................... 5
2.1. Ty p i c a l Connection .......................................................................................................... 5
2.2. Power Interface............................................................................................................... 5
2.3. UART Interface................................................................................................................ 5
2.4. 10/100M Ethernet Interface .......................................................................................... 6
2.4.1.Ethernet Interface with Transformer ..................................................................... 6
2.4.2. Ethernet Interface without Transformer ................................................................ 7
2.5. Reset and Reload............................................................................................................. 8
2.6. Antenna........................................................................................................................... 8
3. Contact ..................................................................................................................................... 9
4. Disclaimer................................................................................................................................. 9
5. Update History.......................................................................................................................... 9

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1.Product Overview
1.1. Dimension
Module dimension diagram as follows:
1.2. Encapsulation
You can download PCB library from http://www.usriot.com/pcb-library-usr-wifi232-a2b2-pcb-library-file/

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1.3. Pin Defination
PIN
Name
Signal Type
Defination
1
GND
P
Power Ground
2
VCC
P
3.3V @ 350mA power input
3
UART_TXD
O
If don’t use UART function, thisfour pins can be
configured as GPIO pins, and can change GPIO pin
status through AT command.
GPIO3
I/O
4
UART_RXD
I
GPIO4
I/O
5
UART_RTS
O
GPIO5
I/O
6
UART_CTS
I
GPIO6
I/O
7
RESET
I
Take effect in low level.
8
nLink
O
Output high level: WIFI connection available.
Output low level: WIFI connection not available.
Can be configured as GPIO.
GPIO8
I/O
9
nReady
O
After module starting, output high level or heartbeat
signal.
Can be configured as GPIO.
GPIO9
I/O
10
nReload
I
Take effect in low level. Press over 3s restore factory
settings.
GPIO10
I/O
1 1
PHY_RX+
I
Ethernet Input+
12
PHY_RX-
I
Ethernet Input-
13
PHY_TX+
O
Ethernet Output+
14
PHY_TX-
O
Ethernet Output-

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2.Hardware Design
2.1. Typical Connection
2.2. Power Interface
USR- WIFI232-A2adopt single-voltage 3.3 V power supply. Peak current is about 350mA, work current is
about 200mA and sleep mode current is 100mA.
The power filter is recommended to be used near the connector of the user board, and it is recommended to
use two parallel decoupling capacitors with 100uF and 10uF to improve the stability of the system and
wireless performance.
2.3. UART Interface
UART is serial data interface that can connect the RS-232 chip and transfer to the RS-232 level. UART
interface includes TXD/RXD/RTS/CTS.Take the RS-232 level as a reference circuit diagram as follows:

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When communicate to MCU with 3.3V, just connecting TXD of module to RXD of MCU and RXD of module to
TXD of MCU. When communicate to MCU with 5V, switching circuit is necessary. Switching circuit diagram
as follows:
2.4. 10/100M Ethernet Interface
2.4.1.Ethernet Interface with Transformer
Put the Ethernet transformer and RJ45 connector on the circuit board can get the standard 10/100M Ethernet
interface.The reference circuit diagram as follows:

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2.4.2 .Ethernet Interface without Transformer
For this application, Ethernet interface will work as internal data interface. Ethernet PHY-to-PHY connection
will use AC coupled connection. This is a space and cost optimized solution.The design should pay attention
to the driving type of PHYchip. PHY chip inside B2 module is current driven, so two side PHYchip are current
drivers can be directly connected.Otherwise, transformer can't be saved. Circuit diagram as follows:
Note: VCC signal at reference design shall base on user board PHY chipset voltage level, such as 2.5V
power supply for general Ethernet PHY chipset.
USR- WIFI232-A2Ethernet interface default is for the application with transformer connection. If user need
PHY-PHY directly connection, please refer to above diagram and use follows AT commands：
AT + VEW = enable < CR > to open Ethernet WAN port (Can restore to default settings by reload)
or AT + FVEW = enable < CR > open Ethernet WAN port (not affected by Reload).
Remark:
1. Only when Ethernet used as WAN, this command is needed. Module default is LAN port.
2. After this command, ensure module WAN IP and LAN IP in different network segment. (Modify the LAN IP

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in AP Settings, modify the WAN IP in STA Settings).
AT + FEPTP = on < CR > Query/Set Ethernet PHY to PHY function ON/OFF
AT + FEPHY = on < CR > Permanently opens the Ethernet function
A T + RELD < CR > Make settings take effect
When user design, should note:
1. Cable connection should be AC coupling and cable need be pulled up to VCC (fit with PHY chip level).
2. Cable TX connected to RX. In PHY-PHY direct connection, PHY chip dose not support direct/ cross
self-adaption.
3. PHY chip on board should better to be forced into 100M work mode.
2.5. Reset and Reload
nReload: nReload pin can connect to external button or configuration pin. Press button over 3s to restore
factory settings. nReload pin should connect to external 4.7k-10k Ohm pull-up resistor. Circuit diagram as
follows:
nReset:Reseting the module and taking effect in low level. nReset pin connect to internal 100K Ohm pull-up
resistor to 3.3V and no need to connect to external pull-up resistor.
2.6. Antenna
USR- WIFI232-A2adpot built-in antenna 2.4GHz antenna that conforms to 802.11b/g/n.The specific
parameters of the antenna as the following table:

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Frequency
2.4~2.5GHz
Impedance
50 Ohm
VSWR
2 (Max)
Return Loss
-10dB (Max)
Connector
On-board Antenna
3.Contact
Company: Jinan USR IOT Technology Limited
Address: Floor 1 1 , Building No.1, No.1166, Xinluo S t r e e t , Gaoxin District, Jinan city,Shandong province,
250101 China
Tel: [phone]
Web:www.usriot.com
Support: h.usriot.com
Email: [e-mail] m
4.Disclaimer
This document provide the information of USR- WIFI232-B2 products, it hasn’t been granted any intellectual
property license by forbidding speak or other ways either explicitly or implicitly. Except the duty declared in
sales terms and conditions, we don’t take any other responsibilities. We don’t warrant the products sales and
use explicitly or implicitly, including particular purpose merchantability and marketability, the tort liability of any
other patent right, copyright, intellectual property right. We may modify specification and description at any
time without prior notice.
5.Update History
2017-07-27 V1.0.0 created.