LG C3380 Service Manual page 28

3.5.2 AD6527 Architecture
The internal architecture of AD6527 is shown above Figure 3-10. AD6527 regroups three main
subsystems connected together through a dynamic and flexible communication bus network. It also
includes onboard system RAM (SRAM) and interfaces with external Flash Memory, Baseband
converter functions, and terminal functions like MMI, SIM and Universal System Connector (USC).
The Digital Signal Processing (DSP) subsystem primarily hosts all the speech processing, channel
equalization and channel codec functions. The code used to implement such functions can be stored
in external Flash Memory and dynamically downloaded on demand into the DSP's program RAM and
Instruction Cache.
The micro-controller subsystem supports all the GSM terminal software, including the layer 1, 2 and 3
of the GSM protocol stack, the MMI, and applications software such as data services, test and
maintenance. It is tightly associated with on-chip system SRAM and also includes boot ROM memory
with a small dedicated routine to facilitate the initialization of the external Flash Memory via code
download using the on-chip serial interface to the external Flash Memory interface.
The peripheral subsystem is composed of system peripherals such as interrupt controller, real time
clock, watch dog timer, power management and a timing and control module. It also includes
peripheral interfaces to the terminal functions: keyboard, battery supervision, radio and display. Both
the DSP and the MCU can access the peripheral subsystem via the peripheral bus (PBUS).
For program and data storage, both the MCU subsystem and the DSP subsystem can access the on
chip system SRAM and external memory such Flash Memory. The access to the SRAM module is
made through the RAM Bus (RBUS) under the control of the bus arbitration logic. Similarly, access to
the Flash Memory is through the parallel External Bus (EBUS).
Figure 3-10. AD6527 Architecture
AD6527/AD6527B AD6527/AD6527B
DSP DSP
Subststem Subststem
DSP BUS DSP BUS
PBUS PBUS
DMA and BUS DMA and BUS
ARBITRATION ARBITRATION
SBUS SBUS
Peripheral Peripheral
Subsystem Subsystem
RF-Control RF-Control
MMI MMI
USC USC
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3. TECHNICAL BRIEF
AD6535
Serial Link
Audio Baseband Audio Baseband
and Power and Power
Management Management
EBUS EBUS
PBUS 1M RBUS 1M
SRAM SRAM
FLASH FLASH