User Guide

CCS Technical Documentation 7 - System Module & UI
Company Confidential NMM-3
Issue 1 (11/2003) Copyright  2003 Nokia Corporation Page 7-19
Company Confidential
SIM Interface
NMM-3’s SIM interface uses the standard DCT4 interface, provided by TIKU and UEME.
This complies with international standard specifications.
The SIM interface signals are protected by SIM EMC/ESD ASIP (R407).
UEME contains the SIM interface logic level shifting. SIM interface can be programmed
to support 3V and 1.8V SIMs. SIM supply voltage is selected by a register in the UEME. It
is only allowed to change the SIM supply voltage when the SIM IF is powered down. The
SIM power up/down sequence is generated in the UEME. This means that the UEME gen-
erates the RST signal to the SIM. Also the SIMCardDet signal is connected to UEME. The
card detection is taken from the BSI signal, which detects the removal of the battery. The
monitoring of the BSI signal is done by a comparator within UEME. The comparator off-
set is such that the comparator output does not alter state as long as the battery is con-
nected. The threshold voltage is calculated from the battery size
specification. The SIM interface is powered up when the SIMCardDet signal indicates
‘card in’. This signal is derived from the BSI signal.
The whole SIM interface locates in TIKU and UEME. The SIM interface in the UEME con-
tains power up/down, port gating, card detect, data receiving, ATR–counter, registers and
level shifting buffers logic. The SIM interface is the electrical interface between the Sub-
scriber Identity Module Card (SIM Card) and mobile phone (via UEME device).
Parameter Min Typ Max Unit
SIMCARDET, BSI comparator threshold 1.94 2.1 2.26 V
SIMCARDET, BSI comparator hysteresis 50 75 100 mV