Figure 112 Keyboard schematics
SIM interface
The UEMCLite contains the SIM interface logic level shifting. The SIM interface can be programmed to support
3V and 1.8V SIMs. SIM supply voltage is selected by with register in the UEMCLite. 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 UEMCLite. This means that the UEMCLite generates the
RST signal to the SIM. In addition, the SIMCardDet signal is connected to UEMCLite. The 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 inside UEMCLite. The comparator offset is such that the comparator outputs do not alter state as
long as the battery is connected. The threshold voltage is calculated from the battery size specifications.
The SIM interface is powered up when the SIMCardDet signal indicates ”card in”. This signal is derived from
the BSI signal.
RM-298; RM-299
System Module
Page 6 –16
COMPANY CONFIDENTIAL
Issue 1
Copyright © 2007 Nokia. All rights reserved.
