Cirrus Logic CS4207 - Manual (Page 138)

138 DS880F4
CS4207
7. APPLICATIONS
7.1 HD Audio Interface
7.1.1 Multi-Channel Streams
The CS4207 codec supports multi-channel streams (streams with sample blocks containing more than
two samples), on both inbound and outbound frames. Each of the 5 output converter widgets (DAC1/2/3,
S/PDIF TX 1/2) can be associated with an individual stream, or multiple widgets can be grouped to share
the same stream. A mix of shared and individual streams is also supported. Furthermore, the order in
which channels are assigned to each widget is not constrained by design. However, the following limita-
tions exist and must be avoided:
• a stream cannot contain channels that are not associated with any widget (unused channels), unless
those channels appear last within the stream packet, after all other channels
• the same channel cannot be associated with more than one widget
The same capabilities and limitations exist for the 3 input converter widgets (ADC1/2, S/PDIF RX). The
following table gives some examples of valid and invalid stream formats:
Table 4. Stream Format Examples
The curly brackets { } delineate each stream packet. The letters within curly brackets designate each
channel within that stream packet. For instance the sequence “{A, B, C, D} {E, F}” denotes two streams -
one stream consisting of 4 channels A-D and one stream consisting of 2 channels E-F.
Stream Format DAC1 DAC2 DAC3 SPDO1 SPDO2 comment
{A,B} {C,D} {E,F} {G,H} {I,J} A, B C, D E, F G, H I, J indiv. streams, in-order assignment
{A, B, C, D, E, F, G, H, I, J} A, B C, D E, F G, H I, J shared stream, in-order assignment
{A, B, C, D} {E, F} A, B C, D E, F - - mixed shared and indiv. streams
{A, B} {C, D} - - C, D - A, B indiv. streams, out of order assignment
{A, B, C, D, E, F, G, H, I, J} G, H E, F A, B I, J C, D shared stream, out of order assignment
{A, B, C, D} - - - C, D - invalid: leading unused ch. (A, B)
{A, B, C, D, E, F, G, H, I, J} A, B E, F G, H I, J - invalid: intermittent unused ch. (C, D)
{A, B, C, D, E, F, G, H, I, J} A, B C, D E, F G, H - ok: trailing unused ch. (I, J)
{A, B, C, D} A, B C, D - A, B - invalid: ch. assigned to mult. widgets