Sim Design Guidelines - Motorola G24 Developer's Manual

SIM Design Guidelines

The SIM interface and signals design is extremely important for proper operation of G24 and the
SIM card. There are several design guidelines that must be followed to achieve a robust and
stable design that meets the required standards and regulations.
•
Using the SIM detection signal, SIM_PD_N, is mandatory in case the SIM card is accessible
to the user and may be removed during G24 operation. To avoid any damage to the SIM or
G24, the SIM interface signals must be deactivated before the SIM card contacts are
mechanically removed from the SIM tray contacts. Therefore, the SIM_PD_N detection
signal must be disabled before the SIM is removed from its tray.
•
The SIM should be located, and its signals should be routed, away from any possible EMI
sources, such as the RF antenna and digital switching signals.
•
The SIM interface signals length should not exceed 100 mm between the G24 interface
connector and the SIM tray. This is to meet with EMC regulations and improve signal
integrity.
•
To avoid crosstalk between the SIM clock and data signals (SIM_CLK and SIM_DIO), it is
recommended to rout them separately on the application board, and preferably isolated by a
surrounding ground plane.
•
The SIM card signals should be protected from ESD using very low capacitance protective
elements (zener diodes, etc.).
•
The G24 interface does not support SIM programming through the VPP signal. This signal
should not be connected to G24.
January 1, 2006
Table 2-5: SIM Interface Signals (Cont.)
Pin # Signal Name
46 SIM_CLK
50 SIM_PD_N
Module Hardware Description
Chapter 2: Hardware Interface Description
Description
Serial 3.25 MHz clock
Active low SIM card presence
detection
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