Cirrus Logic CRD49530-USB - Manual (Page 10)

1-5 Copyright 2008 Cirrus Logic DS705RD3
CRD49530-USB System Description
CRD49530-USB User’s Manual
Audio input data to the DSP can come from any of the following sources:
• CS8416 (U3)
• CS42448 (U4)
• CRD USB Master (feature not currently supported)
• Audio output data from the DSP can be sent to the following destinations:
• CS42448 for conversion to Analog Output (AOUT1 - AOUT8)
• Optical S/PDIF Out (SPDIF_TX), this option disables AOUT7 and AOUT8
The CS4953xx has many applications stored in internal ROM, but a host is still required to configure the
application for a particular system. The CRD49530 allows the PC to act as a host to boot and configure
the DSP through the GUI software.
The CS4953xx can also be booted from external serial flash for custom applications that are not stored in
the DSP’s ROM.
Note: The 144-pin footprint on this board is also compatible with the CS495xx family of DSPs. The
CRD49530 can support any CS495xx chip if the alternate stuffing options shown on the DSP
schematic page have been followed.
1.3.7 CS8416 S/PDIF RX
The CS8416 (U3) is a 192 kHz S/PDIF receiver with an integrated input multiplexer. All of the S/PDIF
input jacks (RX0-RX3) are connected to the CS8416. The active S/PDIF jack is selected by changing the
internal mux through the serial host port of the CS8416. This selection is controlled through the Audio In
configuration within DSP Composer (see
Chapter 4 for details).
When S/PDIF audio is being processed, the CS8416 must master MCLK for the system (see " Audio
Clocking" on page 1-6 for details).
1.3.8 CS42448 Audio Codec
The CS42448 (U4) is a high-performance, multi-channel audio codec capable of supporting sample rates
up to 192 kHz on its 6 ADCs and 8 DACs. This device is used for all analog-to-digital and digital-to-analog
conversions on the CRD49530.
All analog inputs (AIN1-AIN6) and all analog outputs (AOUT1-AOUT8) are connected to the CS42448.
The microphone input shares the AIN5 ADC with the AIN5 RCA jack. When the microphone is in use, the
AIN5 RCA jack is ignored.
When analog audio is being processed, the 24.576 MHz crystal for the CS4953xx must master MCLK for
the system (see "
Audio Clocking" on page 1-6 for details).
1.3.9 Memory
The CRD49530 is populated with a 4 Mbit serial flash. There are 2 footprints (U11, U13) on the board for
compatibility with both standard 8-pin serial flash pinouts. The serial control lines are shared by both
footprints. Only one serial flash chip can be populated.
The CS4953xx can use external SDRAM (U7) to implement features such as large multi-channel audio
delays. A 64 Mbit SDRAM (166 MHz) is connected to the 150 MHz memory bus of the CS4953xx.
There is an additional unpopulated footprint for a parallel flash (U6) memory device. This device was
routed on the board as an example of how to route the memory bus when using a parallel flash memory,