CLM920_NC2_LTE M.2 Module Hardware Usage Guide
Shanghai Yuge Information Technology co., LTD
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The SIM card circuit is susceptible to interference, causing no card recognition or card
loss. The card slot should be placed as far as possible from the RF radiation of the
antenna. The card trace should be as far away as possible from the RF line, VBAT and
high-speed signal line.
The UIM_DATA has been internally pulled up to USIM_VCC through a 47K resistor, and
no external pull-up is required.
USIM_DET inserts or does not insert the detection pin for the USIM card. It is high by
default. The SIM card status is detected by this PIN pin during hot plug application.
The ground of the USIM card and the ground of the module should be well connected,
and the UIM_CLK is protected separately.
3.6.2 USIM_DET Hot Swap Reference Design
The CLM920_NC2 M.2 module supports SIM card hot swapping.
The USIM_DET pin acts as an input detection pin to determine whether the SIM card is
inserted or not. The UIM_DET pin defaults to a pull-up high.
Table 3-8 SIM card hot swap detection pin definition
NO
UIM_DET status
Functional description
1
high
SIM card insertion, UIM_DET is high
2
low
SIM card is pulled out, UIM_DET is low
Figure 3-11 SIM card hot swap detection
It is recommended to add a diode protection next to the UIM _DET pin of the module.
When using a normally closed SIM or a normally open SIM card, the detection function
can be set by the AT command.
