User Guide

NPM-2NX
System Module CCS Technical Documentation
Page 22 ãNokia Corporation Issue 1 07/02
The transmit of the IR module goes as follow. Transmit is controlled by TXD line which
comes from UPP. Between UPP and IR module there is UEM which makes lever-shifter
from 1.8V to 2.78V. VBAT gives power supply to transmit led and serial resistor (R350)
limits current. There is also filter capacitor (C351) on VBAT-line to give proper voltage.
Receiving infrared data to IR led, it goes straight to UEM by RXD line.
VFLASH1 is the power supply of the IR module, except for transmission. That is also fil-
tered by capacitor C350. The IR module has one-control pin to control shut down. Com-
ponent V350 is control-lever-shifter which is used to change proper voltage to IR
module from UPP (GENIO(10) for shutdown.
Figure 9: IR interface
Technical information
The IR interface is designed into the UEM. The IR link supports speeds from 9600 bit/s to
1.152 MBit/s, up to 1m. A special baud rate is used for the NMP specific speech and con-
trol information transmission. This dedicated protocol has special HW support for
extracting the audio and control information from each other.
Charger IF
Introduction
UEM