LG C3400 Service Manual page 24

3.5.2 AD6527B Architecture
The internal architecture of AD6527B is shown above Figure 3-10. AD6527B 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).
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
Figure 3-10. AD6527B Architecture
- 23 -
3. TECHNICAL BRIEF
AS6535 AS6535
SErial Link SErial Link
Audio Baseband Audio Baseband
and Power and Power
Management Management
PBUS 1M PBUS 1M
SRAM SRAM
FLASH FLASH
EBUS EBUS