CLM920 TD3 LTE Module Hardware Usage Guide
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3.7.2 UIM_DET Hot Swap Reference Design
The CLM920 TD3 module supports the USIM card hot plug function. The UIM_DET
pin acts as an input detection pin to determine whether the USIM card is inserted or not. The
UIM_DET pin defaults to a pull-up high. The hot plug function can be turned on or off by
AT+HOSCFG. This function is off by default (see the 9X07 AT command set for details).
Table 3-13 SIM card hot swap detection pin definition
NO.
AT command
UIM_DET status Functional description
1
AT+HOSCFG=1,1 high
SIM card insertion, UIM_DET is high
2
AT+HOSCFG=1,0 low
SIM card insertion, UIM_DET is low
Figure 3-17 Hot swap detection of the USIM card
It is recommended to add a diode protection next to the UIM_DET pin of the module.
When using a normally closed SIM card holder or a normally open SIM card holder, the
detection function can be set by the AT command. If AT+HOSCFG=1 is set, the status of
the SIM card is high when the SIM card is in position, and AT+HOSCFG=1 is set. When
the SIM card is in the state, the status is low. Set AT+HOSCFG=0, 0 SIM card hot swap
function is off.
3.8 General purpose GPIO interface
The CLM920 TD3 module contains five general control signals. The interface is defined
as follows
：
Table 3-14 General GPIO Pin Definitions
Pin Signal name I/O Description
param
eter
Level value (V)
Remarks
Min Typical Max
