User Manual

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Meanwhile, when the module is set to be FU2 mode in FU1 and FU3 mode, the baud
rate exceeding 4,800bps will be automatically reduced to be 4,800bps. In FU2 mode,
the sending time interval of data package cannot be too short; otherwise, the data will
be lost. It is suggested that the sending time interval of data package should not be
less than 1sec.
The following gives some characteristics reference values of various modes:
Mode FU1 FU2 FU3 Remark
Idle current 3.6mA 80μA 16mA Average value
Transmission
time delay
15-25mS 500mS 4-80mS Sending one byte
Loopback
test time
delay 1
31mS Serial port baud rate
9,600, sending one byte
Loopback
test time
delay 2
31mS Serial port baud rate
9,600, sending ten bytes
Note: Loopback test time delay means the duration from the time of, after conducting
short circuit on TX and RX pins of one module and sending serial port data to the
other module, starting to send serial port data to the other module to the time that the
returned data appear at TX pin of the other module.
Module Parameter Setting AT Command
AT command is used to set the module parameters and switch the module functions,
and after setting, it will be valid only after exiting from setting state. Meanwhile,
modification of parameters and functions will not be lost in case of power failure.
(1) Command mode entering
The first way to enter: in normal use (energized), put Pin 5 “SET” in low level;
The second way to enter: disconnect power supply, first put Pin 5 “Set” in low level,
and then energize it;
Either of the above two ways can make the module enter AT command mode; release
it (not put pin “SET” in low level), and exit from the command mode. If the module
function is changed after exiting from command mode, it will be switched to
corresponding functional status.
In the second way, the module enters AT in the serial port format of 9,600, N, 1
constantly.
(2) Command instruction
①
. AT
Test command.