SI4438 Wireless Module
User Manual of E30 Series Modules
Copyright ©2012–2017, Chengdu Ebyte Electronic Technology Co., Ltd.
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6.4 Power-saving Mode (Mode 2)
When M1 = 1 & M0 = 0, module works in mode 2
Transmitting
UART is closed, the module cannot receive any serial port data from outside MCU.
Hence the function of wireless transmission is not available for the module working in this mode.
Receiving
In mode 2, it is required the data transmitter works in mode 1.
The wireless module monitors the preamble code at regular time.
Once it gets the preamble code, it will remain as receiving status and waiting for the completion of receiving the entire
valid data package.
Then the AUX outputs low level, 5ms later the serial port is open to transmit received wireless data through TXD. Finally,
AUX outputs high level after process completed.
The wireless module stays in “power-saving – monitoring” working status (polling).
By setting different wake-up time, the module will have different receiving response delay (2s in maximum) and average
power consumption (30uA in minimum).
The user needs to achieve a balance between communication delay time & average power consumption.
6.5 Sleep Mode (Mode 3)
When M1=1, M0=1, module works in mode 3
Transmitting
N/A
Receiving
N/A
Parameter
setting
This mode can be used for parameter setting. It uses serial port 9600 & 8N1 to set module working parameters through
specific instruction format. (please refer to parameters setting for details)
Notes
When the mode changes from sleep mode to others, the module will reset its parameters, during which the AUX keeps low
level and then outputs high level after reset completed. User is recommended to check the AUX rising edge.
7. Instruction Format
In sleep mode（mode 3：M1=1, M0=1）, it supports instructions in the table below.
(
Only support 9600 and 8N1 format when setting
)
No.
Instruction format
Illustration
1
C0 + working parameters
C0 + 5 bytes working parameters are sent in hexadecimal format. 6 bytes in total and must
be sent in succession.
( Save the parameters when power-down )
2
C1+C1+C1
Three C1 are sent in hexadecimal format. The module returns the saved parameters and
must be sent in succession.
3
C2 + working parameters
C2 + 5 bytes working parameters are sent in hexadecimal format. 6 bytes in total and must
be sent in succession. ( Do not save the parameters when power-down )
4
C3+C3+C3
Three C3 are sent in hexadecimal format. The module returns the version information and
they must be sent in succession.
5
C4+C4+C4
Three C4 are sent in hexadecimal format. The module will reset one time and they must be
sent in succession.
