User's Manual

XT55/56 Hardware Interface Description
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XT55/56_hd_v02.06a Page 63 of 125 17.12.2004
3.11.2 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
XT55/56 reference setup, see [8]). X503 is the designation used for the SIM card holder in
[8].
Molex card holder
GSM module
GSM_CCVCC
GSM_CCIN
GSM_CCIO
GSM_CCCLK
GSM_CCRST
GSM_CCGND
47pF
Figure 19: SIM card holder of DSB45 Support Box
Table 16: 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 GSM_CCVCC
8 CCDET2 Connects to the GSM_CCIN input of the GSM engine. Serves to
recognize whether a SIM card is in the holder.
Pins 1 through 8 (except for 5) are the minimum
requirement according to the GSM Recommendations,
where pins 7 and 8 are needed for SIM card tray
detection through the GSM_CCIN pin.
Figure 20: Pin numbers of Molex SIM card holder on DSB45
Support Box
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.
4
5
1
2
7
8
3
6