LG KG920 Service Manual page 34

3. TECHNICAL BRIEF
3.5.2 AD6527 Architecture
Figure 3-10. 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).
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