Only For Training And Service Purposes - LG GM750 Service Manual

3. Technical Brief
3.9.5. Serial Bus Interface(SBI)
The MSM7200A device's SBI is designed specifically to be a quick, low pin count control protocol
for QUALCOMM's RTR6285 and PM7540 ASICs. Using the SBI, the RTR6285 and PM7540 devices
can be configured for different operating modes and for minimum power consumption, extending
battery life in Standby mode. The SBI also controls DC baseband offset errors.
3.9.6. Wideband CODEC
The MSM7200A 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 MSM6280 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 externally. The Rx/Tx paths are designed to meet the ITU-G.712 requirements for digital
transmission systems.
3.9.7. Vocoder Subsystem
The MSM7200A 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 MSM7200A
device's integrated ARM9TDMI processor downloads the firmware into the QDSP4000 and
configures QDSP4000 to support the desired functionality.
3.9.8. ARM Microprocessor subsystem
The MSM7200A device uses an embedded ARM1136-J, 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 serial bus interface (SBI) the ARM926EJ-S configures and controls the
functionality of the RTR6285 and PM7540 devices.
3.9.9. Mode Select and JTAG Interfaces
The mode pins to the MSM7200A 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 MSM7200 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.
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Only for training and service purposes