LG W3000 Service Manual page 34

3. TECHNICAL BRIEF
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 39 MHz at 2.45 V. 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.
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