MeiG_SLM320_Hardware Design Manual
MeiG Smart Technology Co., Ltd
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3.7 USIM/SIM Interface
SLM320 supports both 1.8V and 3.0V SIM cards.
Table 7 USIM/SIM interface description
Pin Name
I/O
Pin
Pin description
USIM_DATA
I/O
15
USIM/SIM
data signal
USIM_CLK
O
16
USIM/SIM
clock signal
USIM_RESET
O
17
USIM/SIM
reset signal
USIM_VDD
O
14
USIM/SIM Power
USIM_PRESENCE
I
13
USIM/SIM
Hot swap detection signal
SLM320 module supports USIM card hot-plugging function through SIM0_DET pin and supports high
level detection. After SIM card is inserted in the figure, SIM0_DET pin is at high level. When SIM0_DET
pin is at low level, no card is detected.
The SIM card hot swap function can be configured by the "AT+SIMHOTSWAP" command. The
instructions of the AT command are shown in the following table:
Table 8 description of hot swap function setting of SIM card
AT Command
SIM card hot
swap detection
Function declaration
AT+SIMHOTSWAP=1
Open
By default, the SIM card hot-plug detection function
is on, and the module detects whether the SIM card
is inserted through the USIM_PRESENCE pin
status
AT+SIMHOTSWAP=0
Close
The SIM card hot-plug detection function is turned
off. The SIM card will be read by the module when
the machine is turned on. The USIM_PRESENCE
status will not be detected
After the hot swap detection function of SIM card is turned on, when sim0_ Det is high level. If the
module detects that the SIM card is inserted, it will execute the SIM card initialization procedure. After
reading the SIM card information, the module will register the network. When sim0_ When det is low
power level, the module determines that the SIM card is pulled out, then the SIM card is not read. SIM0_
Det is valid in high level by default and can be switched to low level by AT command.