cx25840 Conexant Systems, Inc., cx25840 Datasheet - Page 17

• Manufacturer Part Number: cx25840
• Description: Video Decoder And Broadcast Audio
• Manufacturer: Conexant Systems, Inc.

CX25840/1/2/3 Data Sheet
1.1.2.3
1.1.3
102284B
8/3/05
Communication and General Features
Audio Processing
In addition to the demodulation of broadcast audio in the CX25840/1/2/3, premium
functions such as three-band equalization, volume, balance, mute, and automatic
volume control are independently available on both the broadcast audio and serial
audio data streams. The audio samples can also be locked to the incoming video
stream to ensure that the audio samples are rate-matched to the video, eliminating the
need for MPEG encoders to drop or repeat frames in order to keep the video and audio
in sync. The entire audio data path is a minimum of 16 bits wide to maintain CD
quality performance levels throughout the audio signal chain.
Communication with the device is configurable through a pin strap option at power-up
reset. Two methods of communication are available: either a 400 kHz two-wire serial
command interface or a 2-bit VIP host port interface. A hardware interrupt pin is
available along with a maskable interrupt status register so that the device can notify
the system when internal events occur without the need to implement polling
schemes.
Other convenience features consist of the following:
Programmable infrared transmitter/receiver logic, able to modulate or demodulate
low data rate consumer remote control protocols
General purpose I/O pins
Power-down pin or register-controlled power-down levels
Single 3.3 V power supply configuration available with an external pass transistor
PLL output for either supplying a video locked 256x/384x oversample audio clock
or a general purpose user programmable clock for minimizing PCB component
count
Small package size: a 80-pin, 12x12 mm TQFP
All parts are only available in a lead-free package, beginning with -23. Starting
with -24, this is indicated with a “Z” following the dash number, i.e., “-24Z.”
Conexant
Functional Overview
1-5