Cirrus Logic CK4970x4 - Manual (Page 17)

CK49x System Description
CK49x User’s Manual
DS898CK7 Copyright 2012 Cirrus Logic, Inc 1-10
1.3.17 HDMI Recevier (RX)
The Silicon Image ™ Si9135 HDMI Rx (U16) is used for the HDMI input on the CK49x. It can provide up to
4 lines of I 2 S data which can support PCM, legacy compressed audio (DD, DTS), and new HD audio
streams.
Because the Si9135 responds to all I 2 C addresses, a bus isolator (U14) has been used to prevent the
HDMI Rx from responding to serial communication intended for other devices on the CK49x.
1.3.18 HDMI Transmitter (TX)
The Silicon Image Si9134 HDMI Tx (U19) is used for the HDMI output on the CK49x.
Note:
The HDMI Tx function is currently not supported on the CK49x.
Because the Si9134 responds to all I 2 C addresses, a bus isolator (U14) has been used to prevent the
HDMI Tx from responding to serial communication intended for other devices on the CK49x.
1.3.19 Memory
The CDB49x is assembled with a 32-Mbit serial Flash (U13).
The CS495xxx/CS497xxx can use external SDRAM (U15 on DC4953x) to implement features such as
large multi-channel audio delays. A 16 Mbit SDRAM (200 MHz) is connected to the 150 MHz memory bus
of the CS495xxx/CS497xxx.
1.3.20 Audio Clocking
Clocking architecture is one of the most important aspects of an audio system. The input and output clock
domains of the DSP must be synchronous when delivering audio data in an isochronous fashion (constant
bit-rate delivery), even if the input/output domains operate at different frequencies (e.g. 48 kHz input/96
kHz output). Systems utilizing I
2 S delivery of S/PDIF input, ADC input, or other digital audio input use
isochronous delivery.
The requirements are slightly more complicated for systems using “bursty” delivery on the input side of the
DSP, but the CK49x is designed to emulate isochronous systems.
The CK49x can operate in three different clocking modes. Each of these modes is explained in the
following sections.