U8655
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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9
Principles and Failure Analysis
9.1 Block Diagram
The MSM7X2XA (the U8655N uses the MSM7225A) is the baseband signal processing chip,
mainly responsible for processing the input and output of IMGE, VIDEO, AUDIO, MEMEO
SUPPORT, RF INTERFACES, and CONECTIVITY signals. The baseband chip provides
keypad, LCD, SD card, Wi-Fi, Bluetooth, camera, and microphone interfaces.
The PM8029 is mainly responsible for:
Detecting the connection and disconnection of the external power supply.
Supplying power to the phone.