LG CU920 Manual page 53

3.7.11 Serial Bus Interface(SBI)
The MSM6281 device's SSBI is designed specifically to be a quick, low pin count control protocol for
QUALCOMM's RTR6275, RFR6275 and PM6650 ASICs. Using the SSBI, the RTR6275, RFR6275,
and PM6650 devices can be configured for different operating modes and for minimum power
consumption, extending battery life in Standby mode. The SSBI also controls DC baseband offset
errors.
3.7.12 Wideband CODEC
The MSM6281 device integrates a wideband voice/audio CODEC into the mobile station modem
(MSM). The CODEC supports two differential microphone inputs, one differential earphone output, one
single-ended earphone output, and a differential analog auxiliary interface.
The CODEC integrates the microphone and earphone amplifiers into the MSM6281 device, reducing
the external component count to just a few passive components.
The microphone (Tx) audio path consists of a two-stage amplifier with the gain of the second stage set
interally. The Rx/Tx paths are designed to meet the ITU-G.712 requirements for digital transmission
systems.
3.7.13 Vocoder Subsystem
The MSM6281 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 MSM6281 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 MSM6281 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.
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3. TECHNICAL BRIEF
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