System Overview
The MT6217 is a highly integrated single chip solution for
GSM/GPRS phone. Based on 32-bit ARM7EJ-STM RISC
processor, MT6217 features not only high performance
GPRS Class 12 MODEM but is also designed with support
for the wireless multi-media applications, such as
advanced display engine, hardware JPEG decoder,
synthesis audio with 64-tone polyphony, digital audio
playback, Java acceleration, MMS and etc. Additionally,
MT6217 provides varieties of advanced interfaces for
functionality extensions, like 8-port external memory
interface, 3-port 8/16-bit parallel interface, NAND Flash,
IrDA, USB and MMC/SD/MS/MS Pro. The typical
application can be shown as Figure 1.
External Memory Interface
Providing the greatest capacity for expansion, the MT6217
supports up to 8 state-of-the-art devices with SRAM-like
interface, including burst/page mode Flash, page mode
SRAM, Pseudo SRAM, Color/Parallel LCD, and
multi-media companion chip, like Camera and Melody
chips. Regarding the consideration of power consumption
and low noise, this interface is designed for flexible I/O
voltage and allows for lowering supply voltage down to
1.8V. In addition, the driving strength is configurable that
makes the signal integrity problem easy. Retention
technology is also specifically used on data bus to prevent
the bus from being floating during turn over.
Multi-media Subsystem
In order to provide more flexibility and bandwidth for
multi-media products, an additional 8/16 bit parallel
interface is incorporated. This interface is designed
specially for support with Camera companion chip as well
as LCD panel. Moreover, it can connect NAND flash
device to provide a solution for multi-media data storage.
For running multi-media application faster, MT6217
integrates also several hardware-based engines. With
hardware based JPEG decoder, the MT6217 easily handles
real-time playback of compressed image. With hardware
based Resizer and advanced display engine, it can display
and combine arbitrary size of images with up to 4 blending
layers.
User Interface
For user interactions, the MT6217 brings together all
necessary peripheral blocks for multi-media GSM/GPRS
phone. It comprises the Keypad Scanner with capability of
multiple key pressing, SIM Controller, Alerter, Real Time
Clock, PWM, Serial LCD Controller and General Purpose
Programmable I/Os. For connectivity and data storage, the
MT6217 consists of UART, IrDA, USB 1.1 Slave and
MMC/SD/MS/MS Pro. Besides, for large amount of data
transfer, high performance DMA (Direct Memory Access)
and hardware flow control are implemented, that greatly
enhances the performance and saves precious processing
power.
Audio Interface
With highly integrated mixed-signal Audio Front-End, the
MT6217 completes an architecture that allows for easy
audio interfacing with direct connection to the audio
transducers. Not only D/A and A/D Converters for Voice
Band, but also the high resolution Stereo D/A Converters
for Audio band are integrated. In addition, the MT6217
provides also Stereo Input and Analog Mixer. All of them
enable the MT6217 based terminal a rich platform for
multi-media applications.
Radio Interface
Providing a well-organized radio interface with flexibility
for efficient customization, the MT6217 integrates
mixed-signal Baseband Front-End. It carries out gain and
offset calibration mechanisms and filters with
programmable coefficients for comprehensive
compatibility control on RF modules. The approach is also
combining a high resolution D/A Converter for controlling
VCXO or crystal instead of TCVCXO to reduce the
overall system cost. On the other hand, with 14-bit high
resolution A/D Converter for RF downlink path, MT6217
achieves great quality of MODEM performance. Besides,
to remove the necessary of external current-driving
component, the driving strength of some BPI outputs is
designed to be configurable.

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