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5.2. Baseband Overview
The Baseband circuits of the phone are required to perform the following functions:
8
Equalization
8
Channel coding / decoding
8
Speech coding / decoding
8
Data Encryption
8
Layer 1, 2 and 3 software tasks
8
Man Machine interface (MMI)
8
System Interface
8
SIM Interface and Management
8
Audio and Tone Generation
8
Power supply and battery management
8
RF power control
8
Synchronization
8
Real time clock
Figure 5.5. Baseband Block Diagram
The EB-A100 Baseband is built around a GSM chipset developed by Advanced Device. One chip (AD6525) carries out
signal processing with DSP and CPU, and the other chip (AD6537) provides the analogue interface.
The highly integrated nature of the chips means that each contains a large number of functions.
5.2.1. Introduction
GSM Digital
Baaseband
Processor
(AD6525)
Keyboard
R.F. Block
BBCLK
Vibrator
Memory
Flash/SRAM
(32MB/4MB)
RTC
Crystal
LCD Module
MIC
Speaker
SIM
Socket
Keypad Data Bus
CLKIN
OSC
32.768 kHz
Data Bus
Address Bus
LCD Control Bus
A,B,C Serial Port
RF Control Bus
GPIO12
USC Data Bus
SIM Interface
VCC
VBAT
VMEM
TXIQ
RXIQ
Control Signal
VMEM
Handfree Input
HANDFREEIN
GPIO6
Receiver
VMEM
VRTC
VSIM
Buffer
VVCXO
13MHz_BB
VOUTNOR P/N
Phone
Jack
VOUTAUXP
VOUTLOUDP/N
VINNO R P/N
VINAUXP/N
TX/RX
TX/RX
Analog
Switch
Voice
Data
GPIO13
AIN1P/1N
AOUT1P/1N
AIN2P/2N
AOUT3P/3N
AOUT2P/2N
GSM Analog
Baseband and
Codec & Power
Management
(AD6537)
EXTPWR
Li-Ion
Battery
Power
Jack
Over Voltage
Protect Circuit
PMOSFET
Charging
Circuit
VBAT
VCORE
VMEM
VEXT
VSIM
VRTC
VABB
VVCXO
VMIC
RTC
Battery
PJ_FUNC_SEL
PJ_FUNC_SEL
VCORE
VVCXO
VEXT
VMEM
VSIM
VRTC
VABB
VMIC
Backlight
LED
BACKLIGHT
VBAT
LIGHT 1/2/3