Sim Card Fault - Nokia 6260 RM-25 Service Manual

RM-25
Nokia Customer Care Baseband troubleshooting

SIM card fault

The whole SIM interface is located in two chips: UPP_WD2 and UEME. UEME contains the SIM interface logic level
shifting. UPP_WD2 provides SIMClk through UEME to the SIM. The SIM interface supports both 3V and 1.8V SIMs.
There is an EMIF component (3 lines EMI filter) between the SIM card and the UEME which isn't shown in the
figure below.
Figure 88 UPP_WD2 and UEME SIM connections (simplified)
The SIM power up/down sequence is generated in the UEME. This means that the UEME generates the RST signal
to the SIM. The card detection is taken from the BSI signal, which detects the removal of the battery. A comparator
inside the UEME monitors the BSI signal from the SimCardDet input. The threshold voltage is calculated from
the battery size specifications.
First, the SW attempts to power up the SIM with 1.8V. If this does not succeed, power up is repeated with VSIM
switched to 3V.
The data communication between the card and the phone is asynchronous half duplex. The clock supplied to
the card is in GSM system 1.083MHz or 3.25MHz. The data baud rate is SIM card clock frequency divided by 372
(by default), 64, 32, or 16.
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