LG W3000, Service Manual, Page: 34 / 137

3. TECHNICAL BRIEF
- 33 -
MCU subsystem
It consists of an ARM7TDMI central processing unit, a boot ROM, a clock generation and access
control module.
The maximum clock frequency for the ARM7TDMI is 39MHz at 2.45V
The main clock is 13MHz and it is provided by VCTCXO. The Clock & BS(Bus Select) generator
make internal clock by multiplying the main clock by 1X, 1.5X, 2X and 3X
The boot ROM contains MCU code for basic communication between the ARM and one of the
serial ports in the Universal System Connector subsystem.
Peripheral subsystem
It contains four major groups of elements.
The MMI group is a collection of all the functionality that are needed to implement a complete
user interface including keyboard, display, backlight, RTC, general purpose I/O etc.
House Keeping group consists of three different sub-modules: The Watch Dog Timer, the
Interrupt Controller, and the general timers.
GSM system group consists of the time base generation together with the synthesizer interface,
which form the radio control.
Direct Memory Access is located between the three system buses(PBUS, RBUS and EBUS) and
can move any data from any address location on one system bus to any address location on
another system bus.