Cirrus Logic CDB48500-USB - Manual (Page 18)

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3.1.6 Audio Input Source Multiplexer Selection Headers
The CDB48500-USB includes jumpers to change DSP DAI inputs.
• Source 0: CDB USB MASTER Board, controlled from Software (Refer to Section 4.2.2, “Changing the
Audio Input Source” on page 4-3 )
• Source 1: 2 Channels from CS8416 and 8 channels from (2)CS42448, short pins 2 and 3 of J100
• Source 2: 12 Channels from (2)CS42448 codecs, short pins 1 and 2 of J100
• Reference Designators: U1, U2, U9, U18, and J100
These multiplexers are used to select which audio sources feed the CS485XX DAI pins. When the on-board
sources (CS8416, U3 and CS42448, U4 and U5) are being used, the CDB USB MASTER data cannot be
processed.
The CDB48500 contains a header to connect DAI pins, DAO pins, and clocks to external circuitry. The DAO and
clock pins are
• DAI[5,3:0] feed from J102 header, short pins 1 and 3 on J101
• DAI[5,3:0] feed from on board sources, short pins 3 and 5 on J101
• DAI[4] feed from J102 header, short pins 2 and 4 on J101
• DAI[4] feed from on board sources, short pins 4 and 6 on J101
• The DAO pins and clocks are paralleled to both the on board devices and J102, J103 headers
3.1.7 Cirrus Logic CS485xx Audio DSP
The CS485xx audio DSP (U6) are a family of 32-bit fixed point processors designed specifically for audio
applications. The CDB48500 allows a designer to evaluate the CS485xx DSPs in many different modes of
multi-channel input and output. The 48-pin footprint on this board is compatible with any CS485XX chip.
Audio input data to the DSP can come from any of the following sources:
• CS8416 (U3)
• CS42448 (U4 and U5)
• CDB USB MASTER card
• Header for external codecs (not yet supported)
Audio output data from the DSP can be sent to the following destinations:
• Both CS42448’s for conversion to Analog Output (AOUT_1A - AOUT_6B)
• Optical S/PDIF Out (SPDIF_TX), this option disables AOUT_4A and AOUT_4B
• CDB USB MASTER card
The CS485XX has many applications stored in internal ROM, but a host is still required to configure the
application for a particular system. The CDB48500-USB allows the PC to act as a host to boot and configure the
DSP through the GUI software.
The CS485XX can also be booted from external serial flash for custom applications that are not stored in the
DSP’s ROM.
Note: The 48-pin footprint on this board is also compatible with the CS485XX family of DSPs. The
CDB48500 can support any CS485XX chip if the alternate stuffing options shown on the DSP
schematic page have been followed.