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Information as of 2000-01-10
UDA1335H; Universal Serial Bus (USB) Audio Playback Recording Peripheral (APRP)
The UDA1335H is a stereo CMOS codec incorporating
bitstream converters designed for implementation in
USB-compliant audio peripherals and multimedia audio
applications. The UDA1335H is an adaptive asynchronous
sink USB audio device with a continuous sampling
frequency range from 5 to 55 kHz. It contains a USB
interface, an embedded microcontrolleran
Analog-to-Digital Interface (ADIF) and an Asynchronous
Digital-to-Analog Converter (ADAC).
The USB interface is the interface between the USB,the
ADIF, the ADAC and the microcontroller. The USB
interface consists of an analog front-end and a USB
processor. The analog front-end transforms the differential
USB data into a digital data stream. The USB processor
buffers the incoming and outgoing data from the analog
front-end and handles all low-level USB protocols.
The USB processor selects the relevant data from the
universal serial bus, performs an extensive error detection
and separates control information (input and output) and
audio information (input and output). The control
information is made accessible to the microcontroller.
The audio information received from the PC becomes
available at the digital I/O output or is fed directly to the
ADAC. The audio information to be transmitted to the PC
is delivered by the ADIF or by the digital I2PS-bus interface.
The microcontroller handles the high-level USB protocols,
translates the incoming control requests and manages the
user interface via general purpose pins and an I2PS-bus.
The firmware for the microcontroller must be located in an
external (E)PROM.
The ADAC enables the wide and continuous range of input
sampling frequencies. By means of a Sample Frequency
Generator (SFG), the ADAC is able to reconstruct the
average sample frequency from the incoming audio
samples. The ADAC also performs the sound processing.
The ADAC consists of a FIFO, a unique audio feature
processing DSP, the SFG, digital upsampling filters, a
variable hold register, a Noise Shaper (NS) and a Filter
Stream DAC (FSDAC) with integrated filter and line output
drivers. The audio information is applied to the ADAC via
the USB processor or via the digital I/O input.
The ADIF consists of an Programmable Gain Amplifier
(PGA), an Analog-to-Digital Converter (ADC) and a
Decimator Filter (DF). An Analog Phase Lock Loop (APLL)
or oscillator is used for clocking the ADIF. The clock
frequency for the ADIF can be controlled via the
microcontroller. Several clock frequencies are possible for
sampling the analog input signal at different sampling
rates.
Via the digital I/O-bus, an external DSP can be used for
adding extra sound processing features for the audio
received from the PC.
The UDA1335H supports the digital I/O and the I2PS-bus
interface, with standard I2PS-bus data input format and the
LSB justified serial data input format with word lengths of
16, 18 and 20 bits.
The wide dynamic range of the bitstream conversion
technique used in the UDA1335H guarantees a high audio
sound quality.
General
Sound processing (for digital-to analog conversion)
Document references
Page count File size (kB) Datasheet
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