Integration Manual

LISA-U2 series - System Integration Manual
UBX-13001118 - R25 System description Page 46 of 182
1.8 (U)SIM interface
The high-speed SIM/ME interface is implemented as well as automatic detection of the required SIM
supporting voltage.
Both 1.8 V and 3 V SIM types are supported: activation and deactivation with an automatic voltage
switch from 1.8 V to 3 V is implemented, according to ISO-IEC 7816-3 specifications. The SIM driver
supports the PPS (Protocol and Parameter Selection) procedure for baud rate selection, according to
the values determined by the SIM card.
The VSIM supply output pin provides internal short circuit protection to limit the start-up current and
protect the device in short circuit situations. No additional external short circuit protection is required.
Name
Description
Remarks
VSIM
SIM supply
1.80 V typical or 2.90 V typical
Automatically generated by the module
SIM_CLK
SIM clock
3.25 MHz clock frequency
SIM_IO
SIM data
Open drain, internal 4.7 k pull-up resistor to VSIM
SIM_RST
SIM reset
Table 21: SIM interface pins
☞ A low capacitance (i.e. less than 10 pF) ESD protection (e.g. Infineon ESD8V0L2B-03L or AVX
USB0002RP) must be placed near the SIM card holder on each line (VSIM, SIM_IO, SIM_CLK,
SIM_RST). The SIM interface pins ESD sensitivity rating is 1 kV (Human Body Model according to
JESD22-A114F): higher protection level is required if the lines are connected to an SIM card
connector, since they are externally accessible on the application board.
☞ For more details about ESD immunity precautions for SIM interface pins, see section 2.5.3.
The following SIM services are supported:
 Abbreviated Dialing Numbers (ADN)
 Fixed Dialing Numbers (FDN)
 Last Dialed Numbers (LDN)
 Service Dialing Numbers (SDN)
The SIM Application Toolkit and USIM Application Toolkit (USAT) are supported.
The GPIO5 pin is configured as an external interrupt to detect the SIM card mechanical / physical
presence. The pin is configured as input with an internal active pull-down enabled, and it can sense
SIM card presence only if properly connected to the mechanical switch of a SIM card holder as
described in section 1.8.1.4 and 1.8.1.5:
 Low logic level at GPIO5 input pin is recognized as SIM card not present
 High logic level at GPIO5 input pin is recognized as SIM card present
The SIM card detection function provided by GPIO5 pin is an optional feature that can be implemented
/ used or not according to the application requirements. An Unsolicited Result Code (URC) can be
generated each time that there is a change of status (for more details, see the “simind” value of the
<descr> parameter of +CIND and +CMER commands in the u-blox AT Commands Manual [2]).
All the LISA-U2 series modules provide the additional function “SIM card hot insertion/removal” on
the GPIO5 pin, which can be enabled using the AT+UDCONF=50 command.
For more details on SIM detection function, see section 1.12 as well as the u-blox AT Commands
Manual [2], +UGPIOC, +UDCONF=50 commands.