Usr USR-WIFI232-G2 User manual

USR-WIFI232-G2 SPI Interface User Manua l http://en.usr.cn
Jinan USR IOT Technology Limited
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USR-WIFI232-G2
USR-WIFI232-G2
USR-WIFI232-G2
USR-WIFI232-G2
SPI
SPI
SPI
SPI Interface
Interface
Interface
Interface User
User
User
User Manual
Manual
Manual
Manual V1.0
V1.0
V1.0
V1.0
Product
Product
Product
Product Features
Features
Features
Features :
:
:
:
Support UART/SPI two communication interface, user can freely choose
according to demand.
UART communication mode , please refer to "USR-WIFI232 Low Power
WiFi Module User Manual V2.1"



SPI communication , please refer to this documentation

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1
、
Function Description
The USR-WIFI232-G2 module supports SPI data communication mode, the module
connect with SPI device via 5 pin, using interrupt trigger level to support different clock
polarity and phase four transmission modes, up to 6MHz rate.
1.1 Hardware connect
In SPI communication mode, the module operates in master mode, the connection
circuit as following.
Module SPI pins description:
SPI pins WIFI232-G2
Module pin index
Function description
MOSI Pin 30 SPI data out pin
MISO Pin 27 SPI data in pin
CLK Pin 28 SPI clock signal pin
CS Pin 29 SPI select pins
INTR_I Pin 23 SPI interrupt input pin, if the data
needs to be sent from the slave
device to the master device, the
slave device need to sends an
interrupt to the master device
through the INTR pin.
Low effective.
Master device read data from slave
device when INTR pin is low, and
stop read data when INTR pin is
high.

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1.2 SPI Function Switch Method Description
Use AT command “ AT+SPIEN=on ” to open SPI mode, use “ AT+SPIP ” set
parameters.
AT+ SPIEN set SPI mode, restart to effect, UART will automatic close
AT+SPIP set SPI parameters; master mode, transmission mode, clock
frequency
AT+SPIP=<ms, mode, frequency><CR>
+ok<CR>< LF ><CR>< LF >
Parameters:
ms: m, means master
mode: transmission mode, support 0,1,2,3
frequency: clock frequency, support 6MHz,3MHz,1.5MHz,750KHz,350KHz
Transmission mode corresponding clock polarity (CPOL) and clock phase (CPHA) in
the following table:
SPI Bus Protocol
Mode
CPOL CPHA
0 0 0
1 0 1
2 1 0
3 1 1
1.3 SPI Function Using Introduction
1.
1.
1.
1. SPI
SPI
SPI
SPI data
data
data
data sending
sending
sending
sending (module
(module
(module
(module 


slave
slave
slave
slave device)
device)
device)
device)
When module sends data to slave device, INTR_I pin need to be a high level; and
the module will set CS pin low level. While transmitting, the MSB is first.
2.
2.
2.
2. SPI
SPI
SPI
SPI data
data
data
data receiving
receiving
receiving
receiving (slave
(slave
(slave
(slave device
device
device
device 


module)
module)
module)
module)
When slave device sends data to the module, need to write data to the SPI buffer,
then set INTR_I pin low level, until the data is read by module, and then set INTR_I pin
high level.
Note:
Note:
Note:
Note: While
While
While
While reading
reading
reading
reading data,
data,
data,
data, module
module
module
module don
don
don
don ’
’
’
’ t
t
t
t set
set
set
set CS
CS
CS
CS pin
pin
pin
pin low
low
low
low level.
level.
level.
level.