CLM920_AC3 Module Hardware Usage Guide
Shanghai Yuge Information Technology co., LTD
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from the RF radiation of the antenna. The card trace should be as far away as possible
from the RF, power supply and high-speed signal lines.
There is no pull-up resistor inside USIM_DATA, which requires an external 47K resistor
to be pulled up to VDD_EXT.
USIM_PRESENCE inserts or inserts the detection pin for the USIM card. It is high by
default. The SIM card status can be detected by this PIN pin during hot plug application.
To avoid transient voltage overload, the USIM interface requires a 22R resistor in series
with each other on the signal line path.
The ground of the USIM deck and the ground of the module should maintain good
connectivity.
3.7.2 USIM_ PRESENCE Hot Swap Reference Design
The CLM920 AC3 module supports the hot plugging function of the USIM card. The
USIM_PRESENCE pin acts as an input detection pin to determine whether the USIM card is
inserted or not. The USIM_PRESENCE 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 CLM920
AC3 AT command set for details)
。
Table 3-14 SIM card hot swap detection pin definition
Figure 3-18 Hot swap detection of the USIM card
NO. AT command
USIM_PRES
ENCE status
Functional description
1
AT+HOSCFG=1,1
high
SIM card insertion, detection foot is high
2
AT+HOSCFG=1,0
low
SIM card insertion, detection pin is low
