LG KG320, Руководство по обслуживанию

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3. TECHNICAL BRIEF
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3.4.2 AD6527B Architecture
The internal architecture of AD6527B is shown above Figure 3-7. 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 3-7. AD6527B Architecture