Nokia 8550 Service Manual

NSM–3/3D
System Module

PAMS Technical Documentation

Page  12

Issue 4  02/2002

 Nokia Corporation

This section describes the external electrical connection and interface lev-
els on the baseband. The electrical interface specifications are collected
into tables that covers a connector or a defined interface.

DC (charger) connector is physically integrated in the same component
with the accessory interface connector. DC connector has both jack and
contact pads for desk stand.

MBUS

Serial clock

from the

Prommer

0

2.0

logic low

logic low

0.8

2.85

V

Prommer detection and Seri-

al Clock for synchronous

communication

FBUS_RX

Serial data

from the

Prommer

0

2.0

logic low

logic high

0.8

2.85

V

Receive Data from

Prommer to Baseband

FBUS_TX

Data ac-

knowledge to

the Prommer

0

2.0

logic low

logic high

0.5

2.85

V

Transmit Data from Base-

band to Prommer

GND

 GND

0

0

V

Ground

The service connector is used as a flash programming interface for up-
dating (i.e. re–programming) the flash program memory and an electrical
access for services to the engine.

When the flash prommer is connected to the phone supply power is pro-
vided through the battery contacts and the phone is powered up with a
pulse given to the BTEMP line.

The BSI contact on the battery connector is used to detect when the bat-
tery is to be removed to be able to shut down the operations of the SIM
card before the power is lost if the battery is removed with power on. The
BSI contact disconnects earlier than the supply power contacts to give
enough time for the SIM and LCD shut down.

VBATT

3.0

3.9

4.2

V

Battery voltage

BSI

0

2.85

V

Battery size indication

Phone has 100kohm pull up resistor.

SIM Card removal detection

(Treshold is 2.4V@VBB=2.8V)

67

68

69

kohm

 Battery indication resistor (BLB–2)

0

0

1

kohm

 Battery indication resistor (service  battery)