Vocoder Subsystem - LG U990 Service Manual

3.7.13 Vocoder Subsystem

The MSM6280 device's QDSP4000 supports AMR,FR,EFR and HR. In addition, the QDSP4000 has
modules to support the following audio functions: DTMF tone generation, DTMF tone detection, Tx/Rx
volume controls, Tx/Rx automatic gain control (AGC), Rx Automatic Volume Control (AVC), EarSeal
Echo Canceller (ESEC), Acoustic Echo Canceller (AEC), Noise Suppression (NS), and programmable,
13-tap, Type-I, FIR, Tx/Rx compensation filters. The MSM6280 device's integrated ARM9TDMI
processor downloads the firmware into the QDSP4000 and configures QDSP4000 to support the
desired functionality.
3.7.14 ARM Microprocessor subsystem
The MSM6280 device uses an embedded ARM926EJ-S microprocessor. This microprocessor,
through the system software, controls most of the functionality for the MSM device, including control of
the external peripherals such as the keypad, LCD, RAM, ROM, and EEPROM devices.
Through a generic single serial bus interface (SSBI) the ARM926EJ-S configures and controls the
functionality of the RFR6275, RTR6275, and PM6650 devices.
3.7.15 Mode Select and JTAG Interfaces
The mode pins to the MSM6280 device determine the overall operating mode of the ASIC. The options
under the control of the mode inputs are Native mode, which is the normal subscriber unit operation,
ETM mode, which enables the built-in trace mode, and test mode for factory testing. The MSM6280
device meets the intent of the ANSI/IEEE 1149.1A-1993 feature list. The JTAG interface can be used
to test digital interconnects between devices within the mobile station during manufacture.
3.7.16 General-Purpose Input/Output Interface
The MSM6280 device has general-purpose bidirectional input/output pins. Some of the GPIO pins
have alternate functions supported on them. The alternate functions include USB interface, additional
RAM, ROM, general-purpose chip selects, parallel LCD interface, and a UART interface. The function
of these pins is documented in the various software releases.
3.7.17 UART
The MSM6280 device employs three UARTs. UART1 has dedicated pins while UART2 and UART3
share multiplexed pins.
■ UART1 for data
■ UART2 (can be used for USIM interface)
■ UART3 for data
3.7.18 USB
The MSM6280 device integrates a universal serial bus (USB) controller that supports both
unidirectional and bidirectional transceiver interfaces. The USB controller acts as a USB peripheral
communicating with the USB host.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3. TECHNICAL BRIEF
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