LG VX5400 Service Manual page 31

of terminals. On the SDRAM data generated during the terminal operation are stored temporarily.
2.3.5 Power Supply Part
When the battery voltage (+4.0V) is fed and the PWR key of keypad is pressed, the power-up circuitry in PM
(power management) IC (U500) is activated by the PWR_ON_SW signal, and then the LDO regulators
embedded in PMIC for MSM) are operated and +1.867V_MSMC, +2.85V_MSMP and +2.6V_MSMA are
generated.
The Rx part regulator (+2.85V_RX) is operated by the control signal of SLEEP/ from MSM6100.
The Tx part regulator (+3.0V_TX) is operated by the I
2.3.6 Logic Part
The logic part consists of internal CPU of MSM, RAM, MCP. The MSM6100 receives TCXO (=19.2MHz)
from X100 and controls the phone in both CDMA and FM modes. The major components are as follows:
CPU
The ARM9TDMI microprocessor includes a 3 stage pipelined RISC architecture, both 32-bit ARM and 16-bit
THUMB instruction sets, a 32-bit address bus, and a 32-bit internal data bus. It has a high performance and
low power consumption.
MCP
Flash ROM is used to store the terminal's program. Using the down-loading program, the program can be
changed even after the terminal is fully assembled.
SDRAM is used to store the internal flag information, call processing data, and timer data.
KEYPAD
For key recognition, key matrix is setup using KYPD[1][3][5][7][9][11][13][15][17][19] signal from MSM.
20 LEDs and backlight circuitry are included in the keypad for easy operation in the dark.
LCD MODULE
LCD module contains a controller which will display the information onto the LCD by 16-bit data from the
MSM6100. It is also supplied stable 2.85V_MSMP by regulator in U402 for fine view angle and LCD reflects
to improve the display efficiency. 4 LEDs are used to display LCD backlight.
Copyright@2007 LG Electronics. Inc. All right reserved.
Only for training and serving purposes
2
C control signal from MSM6100.
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