cs5535 National Semiconductor Corporation, cs5535 Datasheet - Page 81

• Manufacturer Part Number: cs5535
• Description: Geode Cs5535 Companion Multi-function South Bridge
• Manufacturer: National Semiconductor Corporation

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4.3
The primary purpose of the AC97 Audio Codec Controller
(ACC) is to stream data between system memory and an
AC97 codec (or codecs) using direct memory access
(DMA). The AC97 codec supports several channels of digi-
tal audio input and output. Hence, the ACC contains sev-
eral bus mastering DMA engines to support these
channels. This method off-loads the CPU, improving sys-
tem performance. The ACC is connected to the system
through the GLIU and all accesses to and from system
memory go through the GLIU. The AC97 codec is con-
nected with a serial interface, and all communication with
the codec occurs via that interface (see Figure 4-3).
Features include:
• AC97 version 2.1 compliant interface to codecs: serial in
• Eight-channel buffered GLIU mastering interface.
• Support for industry standard 16-bit pulse code modu-
• Support for any AC97 codec with Sample Rate Conver-
LBus Clock
(x2), serial out, sync out, and bit clock in.
lated (PCM) audio format.
sion (SRC).
GL Clock
Bit Clock
AC Link
AC97 AUDIO CODEC CONTROLLER
GLCP I/F
CCU
CCU
CCU
Output
Data
Mux
GLIU Data In
GeodeLink Adaptor (GLA)
Figure 4-3. ACC Block Diagram
Registers / Control
81
GLIU Data Out
• Transport for audio data to and from the system memory
• Capable of outputting multi-channel 5.1 surround sound
Hardware Includes:
• GeodeLink Adapter.
• Three 32-bit stereo-buffered bus masters (two for output,
• Five 16-bit mono-buffered bus masters (three for output,
• AC Link Control block for interfacing with external AC97
The ACC logic controls the traffic to and from the AC97
codec. For input channels, serial data from the codec is
buffered and written to system memory using DMA. For
output channels, software-processed data is read from sys-
tem memory and streamed out serially to the codec.
Control Signals to Bus Masters
and AC97 codec.
(Left, Center, Right, Left Rear, Right Rear, and
Low Frequency Effects).
one for input).
two for input).
codec(s).
Bus Master 0
Bus Master 1
Bus Master 2
Bus Master 3
Bus Master 4
Bus Master 5
Bus Master 6
Bus Master 7
To/From Codec
Link
AC
Revision 0.8