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The baseband function reduces part costs by using two external bus
interfaces to support next-generation memory architectures, such as
NAND FLASH, SRAM and pseudo SRAM (PSRAM), page and burst
mode NOR or MLC NOR FLASH, and low-power SDRAM (LP-SDRAM).
The EBI2 also serves as an enhanced LCD interface.
Audio support supplements the analog/RF function’s CODEC, including
MP3 decoding,AAC and AAC+ devices, a Compact Media
Extension™ (CMX™)/MIDI synthesizer, and QCELP®.
The CDMA air interfaces are implemented on the baseband CDMA
processor. All necessary interfaces to the RF functions are provided,
some using a portion of the 57 GPIOs. Many of the AMSS-configurable
GPIOs are available for alternate uses as desired by the wireless
product designers.
Support circuitry and baseband internal functions include security, clock
generation and distribution, JTAG/embedded trace macrocell (ETM) test
interfaces, mode and reset controls, and the Q-fuse.
QCT provides a complete software suite — Advanced Mobile
Subscriber Software™(AMSS™) — for building handsets around the
QSC6085 device.
The GSM platform is MT6223D.It performed as the Modem.QSC6085
communicate with MT6223D by UART.
4.2.2.2 External Memory
CDMA: 256M Byte NAND FLASH + 128M Byte DDR
GSM: 64M bit NOR FLASH + 32M bit pSRAM
4.2.2.3 Power circuit
The input power management portion of its block accepts power from
common sources —the main battery or an external charger — and
generates all the regulated voltages needed to power the appropriate
handset electronics. It monitors and controls the power sources
detecting which sources are applied, verifying that they are within
acceptable operational limits, and coordinates battery and coin cell
recharging while maintaining the handset electronics supply voltages.
On-chip voltage regulators generate ten programmable output voltages
using one switched-mode power supply and nine low dropout voltage
regulators, all derived from a common trimmed voltage reference.