User's Manual
Table Of Contents
- Contents
- Figures
- Tables
- Document history
- Introduction
- Product concept
- GSM application interface
- GSM/GPRS operating modes
- Power supply
- Power up / down scenarios
- Automatic GPRS Multislot Class change
- Charging control of the GSM part
- Power saving
- Summary of state transitions (except SLEEP mode)
- RTC backup for GSM part of XT55/56
- Serial interfaces of the XT55/56 GSM part
- Audio interfaces
- SIM interface
- Control signals
- GPS application interface
- GSM and GPS antenna interfaces
- Electrical, reliability and radio characteristics
- Mechanics
- Reference approval
- Example applications
- List of parts and accessories
XT55/56 Hardware Interface Description
Confidential / Released
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XT55/56_hd_v02.06a Page 61 of 125 17.12.2004
3.11 SIM interface
The baseband processor has an integrated SIM interface compatible with the ISO 7816 IC
Card standard. This is wired to the host interface (board-to-board connector) in order to be
connected to an external SIM card holder. Six pins on the board-to-board connector are
reserved for the SIM interface.
The GSM_CCIN pin serves to detect whether a tray (with SIM card) is present in the card
holder. Using the GSM_CCIN pin is mandatory for compliance with the GSM 11.11
recommendation if the mechanical design of the host application allows the user to remove
the SIM card during operation. See Chapter 3.11.1 for details.
Table 15: Signals of the SIM interface (board-to-board connector)
Signal Description
GSM_CCGND Separate ground connection for SIM card to improve EMC.
GSM_CCCLK Chipcard clock, various clock rates can be set in the baseband processor.
GSM_CCVCC SIM supply voltage from PSU-ASIC
GSM_CCIO Serial data line, input and output.
GSM_CCRST Chipcard reset, provided by baseband processor.
GSM_CCIN Input on the baseband processor for detecting a SIM card tray in the holder.
The GSM_CCIN pin is mandatory for applications that allow the user to remove the
SIM card during operation.
The GSM_CCIN pin is solely intended for use with a SIM card. It must not be used
for any other purposes. Failure to comply with this requirement may invalidate the
type approval of XT55/56.
It is recommended that the total cable length between the board-to-board connector pins on
XT55/56 and the pins of the SIM card holder does not exceed 200 mm in order to meet the
specifications of 3GPP TS 51.010-1 and to satisfy the requirements of EMC compliance.
To avoid possible cross-talk from the GSM_CCCLK signal to the GSM_CCIO signal be
careful that both lines are not placed closely next to each other. A useful approach is using
the GSM_CCGND line to shield the GSM_CCIO line from the GSM_CCCLK line.
Furthermore connect a 47 pF capacitor from the GSM_CCIO to the GSM_CCGND line.