User Guide

CBUS interface

CBUS is a "main" system control bus in BB5.0. RAP controls the functionality of EM ASIC (N2200) and EM ASIC

(N2300) ASICs with CBUS.

CBUS is a four-wire half-duplex master-slave interface. In BB5.0 CBUS clock frequency is 2.4 MHz.

FBUS

USB and FBUS have multiplexed interface between EM ASIC (2300) and RAP.

ACI interface

The ACI (Accessory Control Interface) is a point-to-point, bi-directional, single line serial bus.

It has two main features: the insertion and removal detection of an accessory device and acting as a data

bus between phone and accessory, intended for control purposes. A third function of ACI is to identify and

authenticate the accessory.

VOUT interface

Accessory power is supplied by VOUT, a linear low drop-out regulator in EM ASIC (N2300) providing 2.5V at

90mA maximum when active (0.5mA in sleep).

Charger interface

Charging control and charge switch are situated in EM ASIC (N2300).

If the temperature rises too high and the thermal protection is activated, EM ASIC (N2300) goes to protection

mode.

MicroSD interface

The MicroSD card interface is electrically and functionally compatible with the SD card interface.

SIM/USIM

The device has one SIM (Subscriber Identification Module) interface and the SIM card locates under the battery.

SIM interface consists of internal interface between RAP and EM ASIC (N2200) and an external interface

between Retu and SIM contacts.

EM ASIC (N2200) external SIM IF connections and electrical characteristics between ASICs are shown in the

picture.

RM-198

Nokia Customer Care System Module

Page 8 –10 COMPANY CONFIDENTIAL Issue 1