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5. Circuit Description
5-1
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5-1 Logic Part
5-1-1 Power Supply
Press "END/
ⓛ
" key to turn on the phone and then
the V_BAT signal will be connected to ON_SW,
which turns on the inner regulator (MSMA_2.65V,
MSMP_2.85V) of U204 (RC5T623)
The
V_BAT
applied
to
ON_SW
will
change
ON_SW_SENSE signal from HIGH to LOW. This
will allow MSM6000 (U100) to send out PS_HOLD
(logical HIGH) to turn on the inner regulator even
after the END/
ⓛ
key is released.
The regulated voltage (MSMP_2.85V) is used in
the digital part of MSM6000, Memory, and LCD.
The regulated voltage (MSMA_2.65V) is used in
analog part and MSMC_2.80V used in core part of
MSM6000.
The regulated voltage (RFTX_2.60V) is
used in the TX RF part. The regulated voltage
(RFRX_2.60V) is used in the Rx RF part.
The
regulated voltage (MOTOR_3.0V) is used in motor
part. The regulated voltage
(PAVREF_2.90V) is
used in WS1101 (U447).
The regulated voltage
(U209) LED_3.3V is used in LED.
5-1-2 Logic
The
logic
part
consists
of
the
internal
CPU
(MSM6000) and the extra memory composed of
SRAM
and
FlashROM.
The
MSM6000
receives
32.768KHz TCXO clock signal and controls the
phone as a whole. The major components are as
follows:
- CPU : ARM7TDMI CPU core,
- FROM:U102(K5A3281CTM) 32Mbit Flash ROM,
MCP.
- SRAM:U102(K5A3281CTM) 8Mbit SRAM, MCP.
CPU(U100:MSM6000-208FBGA)
ARM 7TDMI microprocessor is used for the main
processing. The CPU controls all the circuitry. The
MSM6000 derives all of its internal clock sources
from two clock inputs, TCXO (19.20MHz) and
XTAL (32.768KHz).
The clock of 32.768KHz is
used for sleep. This is equipped with the ARM
7TDMI CPU core, CDMA, DFM block, vocoder,
general purpose interface, and other interfaces, and
is one of the most important components of the
CDMA cellular phone.
FROM and SRAM (U102:K5A3281CTM,MCP)
Memories are composed of 32Mbit FROM and
8Mbit SRAM. 32Mbit Flash ROM is used to store
the
FONT
data
and
terminal's
program.
Using
the down-loading program, the program can be
changed even after the terminal is fully assembled.
8Mbit SRAM is used to store the internal flag
information, call processing data, and timer data.
KEYPAD
For key recognition, key matrix is setup using
SCAN(0:6) and KEYSENSE(0:2) of input port of
MSM6000.
12
backlight
LEDs
and
back-light
circuitry
are
included
in
the
keypad
for
easy
operation in the dark.
LCD MODULE
The LCD module is a 128 X 64 dots and 1 fixed
icon. The LCD contains a controller
which will
display the information by 8-bit data from the MCU.
It also contains a DC-DC converter for contrast
adjustment
and
LCD
reflector
to
improve
the
display efficiency. An internal back-light circuitry
and EL back-light are used for easy operation in
the dark.
