LG C1150 Service Manual page 27

3. TECHNICAL BRIEF
3.5.2 AD6527 Architecture
The internal architecture of AD6525 is shown in Figure 3-10. AD6525 regroups three main subsystems
connected together through a dynamic and flexible communication bys 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 suc functions can be stored in
external Flash Memory and dynamically downloaded on demand into the DSP's program RAM and
Instruction Cache.
The microcontroller 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. AD6525 INTERNAL ARCHITECTURE
AD6525
DSP
Subsystem
DSP BUS
DMA and BUS
PBUS
ARBITRARION
SBUS
Peripheral MUC
Subsystem
Subsystem
(ARM7TDMI
RF-Control
MMI
USC
- 28 -
Serial Link
AD6537B
EBUS
RBUS
SRAM
FLASH
®
)