CS4923 Datasheet, PDF (20/56 Pages) Cirrus Logic – Multi-Channel Digital Audio Decoders

CS4923/4/5/6/7/8/9
2. FAMILY OVERVIEW
The CS4923, CS4924, CS4925, CS4926, CS4927,
CS4928 and the CS4929 are system on a chip
solutions for multi-channel (or stereo in the case of
the CS4929) audio decompression and digital
signal processing. Because the parts are primarily
RAM-based, a download of application software is
required each time the CS4923/4/5/6/7/8/9 is
powered up. This document uses “download” and
“code load” interchangeably. These terms should
be interpreted as meaning the transfer of
application code into the internal
CS4923/4/5/6/7/8/9 memory from either an
external microcontroller or through the autoboot
procedure.
This document focuses on the electrical features
and characteristics of these parts. The different
features are described from a hardware design
perspective. It should be understood that not all of
the features portrayed in this document are
supported by all of the versions of application code
available. The application user’s guides (see
section 2.2.2) should be consulted to confirm
which hardware features are supported by the
software. This document will be valuable to both
the hardware designer and the system programmer.
This data sheet covers the CS4923, CS4924,
CS4925, CS4926, CS4927, CS4928 and CS4929.
These parts are identical from an external electrical
perspective. Internally each device has been
tailored for supporting different decoding
standards. For this document CS4923/4/5/6/7/8/9
has been replaced in certain places with CS492X
for readability. Unless otherwise specified
CS492X should be interpreted as applying to the
CS4923, CS4924, CS4925, CS4926, CS4927,
CS4928 and CS4929.
There are two revisions of silicon commercially
available. The features available on Revision D are
a super-set of those features available on Revision
B. Differences between the revisions are pointed
out when features are discussed within this
document. The silicon revision for any chip can be
determined by referencing Table 1 below.
Revision B
CS492301
CS492401
CS492501
CS492603
Revision D
CS492305
CS492405
CS492505
CS492604
CS492705
CS492804
CS492906
Table 1. Silicon Revisions
These parts are generally targeted at two different
market segments. The broadcast market where
audio/video (A/V) synchronization is required, and
the outboard decoder markets where audio/video
synchronization is not required. The important
differentiation is the format in which the data will
be received by the CS4923/4/5/6/7/8/9. In systems
where A/V synchronization is required from the
CS4923/4/5/6/7/8/9, the incoming data is typically
PES encoded. In an outboard decoder application
the data typically comes in the IEC61937 format
(as specified by the DVD consortium). An
important point to remember is that the
CS4923/4/5/6/7/8/9 will support both
environments, but different downloads are required
depending on the input data type.
Broadcast applications include (but are not limited
to) set top box applications, DVDs and digital TVs.
Outboard decoder applications include standalone
decoders and audio/video receivers. Often times a
system may be a hybrid between an outboard
decoder and a broadcast system depending on its
functionality.
As discussed above, compressed audio can be
packed in IEC61937, PES, or elementary formats
depending on the decoder environment. Each for-
mat is supported by a separate download of appli-
cation code. Consult the relevant Application Code
20
DS262F2