Xilinx XAPP169 - Manual (Page 6)

6 www.xilinx.com XAPP169 (v1.0) November 24, 1999
1-800-255-7778
MP3 NG: A Next Generation Consumer Platform R
Crystal CS4343
Stereo DAC
The Digital-to-Analog Converter chosen for this design is the Crystal CS4343 from Cirrus
Logic. This device features:
• 1.8V to 3.3V operation.
• 24-bit conversion at up to 96 kHz.
• Digital volume control.
• Digital bass and treble boost.
• Built-in headphone amplifier capable of delivering 5 mW into a 16 Ω load.
Figure 5 shows the block diagram for this device.
The CS4343 provides three interfaces: the analog stereo headphone interface, the serial port
used to transfer digital audio data streams, and the control port used to configure the device.
The control port is an industry standard I
2
C slave interface. I
2
C is a multidrop, 2-wire, serial
interface consisting of a clock (SCL) and data (SDA) and operating at up to 100 kHz. (See
Figure 7 Control Port Timing.) The control port is used to configure device features such as
volume, muting, equalization, power management, and the operating mode of the serial port.
Figure 1 on page 3 gives an overview of control port timing. A detailed description of I
2
C
operation can be found in the I
2
C specification as described in the references.
LK/DEM
SDATA
DIF1/SDA
MCLK
VA_HP
HP
SERIAL
PORT
DE-
CONTROL PORT
∆Σ
DAC
RST
LRCK
DIF0/SCL
VA
VD_IO
DIGITAL
VOLUME
CONTROL
BASS/TREBLE
BOOST
COMPRESSION
LIMITING
∆Σ
DAC
DIGITAL
FILTERS
ANALOG
FILTER
ANALOG
FILTER
GND FILT+ REF_GND
ANALOG
VOLUME
CONTROL
HEAD-
PHONE
AMPLIFIER
ANALOG
VOLUME
CONTROL
HP
EMPHASIS
VQ_HP
Figure 5: CS4343 Block Diagram
(Courtesy Cirrus Logic)