MC45 Hardware Interface Description
P R E L I M I N A R Y
MC45_HD_01_V00.02a
Page 55 of 90
12.08.2002
3.7.2 Design considerations for SIM card holder
The schematic below is a sample configuration that illustrates the Molex SIM card holder
located on the DSB45 Support Box (evaluation kit used for type approval of the Siemens
MC45 reference setup, see [4]). X503 is the designation used for the SIM card holder in [4].
Molex card holder
GSM module
Figure 20: SIM card holder of DSB45 Support Box
Table 14 : Pin assignment of Molex SIM card holder on DSB45 Support Box
Pin no. Signal name
I/O
Function
1
CCVCC
I
Supply voltage for SIM card, generated by the GSM engine
2
CCRST
I
Chip card reset, prompted by the GSM engine
3
CCCLK
I
Chip card clock
4
CCGND
-
Individual ground line for the SIM card to improve EMC
5
CCVPP
-
Not connected
6
CCIO
I/O
Serial data line, bi-directional
7
CCDET1
-
Connect to CCVCC
8
CCDET2
Connects to the CCIN input of the GSM engine. Serves to
recognize whether a SIM card is in the holder. Removing the SIM
card during operation will immediately stop further transmission of
signals to the card to protect the card from damage.
Pins 1 through 6 are the minimum requirement according to the GSM Recommendations,
while 7 and 8 are needed for the CCIN pin.
Place the capacitors C1205 and C1206 (or instead one capacitor of 200nF) as close as
possible to the pins 1 (CCVCC) and 4 (GND) of the card holder. Connect the capacitors to
the pins via low resistance tracks.
The X507 switch is not mandatory, but may be added to help the system integrator control
the CCIN signal, e.g. for designing and testing purposes. When the switch is pushed open (3
is switched to 2), the line simulates an empty SIM card holder although the SIM is inserted.
When closed (3 connected to 1), the line simulates that the SIM card is present.
