Nokia 5140 Manuales De Servicio

NPL-4/5

System Module and User Interface

Nokia Customer Care

Page 52

 Copyright © 2004 Nokia Corporation. All rights reserved.

Issue 1 05/04

The ASIC supports three magnetometer axis. The ASIC features are:

•

Pre-amplifier followed by a single-shot sigma delta type of ADC for each measurement 
channel

•

H-bridge for driving the SET/RESET coil inside the magnetometer element 

•

Internal voltage reference for the ADC and the magnetometer bridge

•

Digital control interfaces (I2C, CBUS, UART)

•

Control registers

•

One-bit digital control output signal to turn on/off the external linear regulator

The magnetometer interface has three differential inputs for X-, Y- and Z-bridge respec-
tively. The measurement path for each axis can be enabled/disabled separately and the 
power consumption of any unused path is minimized. The magneto-resistive bridges of 
all axes are biased by a single reference voltage (2.2 V) provided by the internal band-
gap reference.

I2C slave interface

 

write cmd,addr
write data (8)

read addr
read data (8)

CBUS interface

 

UART interface

 

write cmd,addr
write data (16)

read addr
read data (16)

write cmd,addr
write data (8)

read addr
read data (8)

CBusClk

 

CBusEnX

 

CBusDa

 

UARTRx

 

CLOCK

 

DIVIDER

 

internal

 

clocks

 

Pre

 

-

 

amplifier

 

Magnetometer

 

SET/RESET

 

generator

 

Clk

 

Single shot

 

measurement

 

counters

 

Sigma-delta ADC

Pre

 

-

 

amplifier

 

Pre

 

-

 

amplifier

 

data

 

REGISTERS

CONTROL

reset

 

ClrX

Sigma-delta ADC

Sigma-delta ADC

Bandgap

 

reference

 

UARTTx

 

VBridge

 

I2CClk

 

I2CDa

 

InX

 

InY

 

InZ

 

2

 

2

 

2

 

3

 

3

 

2

 

2

 

SRVdd

 

SROp

 

SROm

 

TankCharge

 

SRVss

 

RegCtrl

SMC

TMC

DTest1

DTest2

DTest3

DVdd

DVss

AVdd

AVss