CDB47xxx Main Board System Description
CDB47xxx User’s Manual
DS886DB9
Copyright 2012 Cirrus Logic, Inc
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selection header. Pin 1 of each header is marked with a triangle and the word “REG”. Pin 2 of each
header is labeled with the voltage required for that pin (+5V, +3.3V, or +1.8V).
1.3.7 Digital Audio Input Source Multiplexer (U1)
The audio input source multiplexer has the following characteristics:
• Source 1: Optical S/PDIF Input
• Source 2: Coaxial S/PDIF Input
• Source 3: Digital Audio Input (DAI) Header
This multiplexer is used to select which audio source feeds the CS470xx DAI3 pin. When the CS470xx
has DAI3 configured as a S/PDIF receiver, either Source 1 or Source 2 can be selected by the MCU.
When DAI3 is configured as a standard I2S input, Source 3 can be selected as the data source.
The CDB47xxx has been designed to indicate which input is currently selected by illuminating a specific
LED for each Source, as described below:
• Source 1 selected: D12 will be on
• Source 2 selected: D51 will be on
• Source 3 selected: D5 will be on
1.3.8 CS470xx Audio System-On-a-Chip (ASOC)
The CS470xx ASOCs are a family of ICs designed specifically for audio applications. The CDB47xxx
allows a designer to evaluate the CS470xx ASOCs in many different modes of multi-channel input and
output. The 100-pin footprint on the daughtercard is compatible with any CS470xx chip that uses the
LQFP100 package.
Audio input data to the ASOC can come from any of the following sources:
• Line-Level Analog Audio Input Connectors
• Optical S/PDIF Input Connector
• Coaxial S/PDIF Input Connector
• DAI Header
Audio output data from the ASOC can be sent to the following destinations:
• Line-Level Analog Audio Output Connectors
• Optical S/PDIF Output Connector
• Coaxial S/PDIF Input Connector
• DAO Header
The CS470xx can be booted from external serial Flash for custom applications in which a host MCU is not
desired.
The CDB47xxx also allows the PC to act as a host to boot and configure the DSP through the GUI
software for real-time configuration of the audio processing.
