cs4237b Cirrus Logic, Inc., cs4237b Datasheet - Page 29

• Manufacturer Part Number: cs4237b
• Description: Crystalclear Advanced Audio System With 3d Sound
• Manufacturer: Cirrus Logic, Inc.

Sound System Codec Register Interface
The Windows Sound System codec is mapped
via four locations. The I/O base address,
WSSbase, is determined by the Plug and Play
configuration. The WSSbase supports four direct
registers, shown in Table 3. The first two direct
registers are used to access 32 indirect registers
shown in Table 4. The Index Address register
(WSSbase+0) points to the indirect register that
is accessed through the Indexed Data register
(WSSbase+1).
This section describes all the direct and indirect
registers for the WSS Codec. Table 5 details a
summary of each bit in each register with Ta-
bles 6 through 15 illustrating the majority of
decoding needed when programming the WSS
logical device, and are included for reference.
When enabled, the WSS Codec default state is
defined as MODE 1. MODE 1 is backwards
compatible with the CS4248 and only allows ac-
cess to the first 16 indirect registers. Putting the
part in MODE 2 or MODE 3, using CMS1,0 bits
in the MODE and ID register (I12), allows ac-
cess to indirect registers 16 through 31. Putting
the part in MODE 3 also allows access to the
extended registers through I23 and other ex-
tended features in the indirect registers.
DIRECT MAPPED REGISTERS
The first two WSS Codec registers provide indi-
rect accessing to more codec registers via an
index register. The other two registers provide
status information and allow audio data to be
transferred to and from the WSS Codec without
using DMA cycles or indexing.
Note that register defaults are listed in binary
form with reserved bits marked with ’x’ to indi-
cate unknown. To maintain compatibility with
future parts, these reserved bits must be written
as 0, and must be masked off when the register
is read. The current value read for reserved bits
is not guaranteed on future revisions.
DS213PP4
Direct Registers: (R0-R3)
WSSbase+0
WSSbase+1
WSSbase+2
WSSbase+3
Index
Address
I10
I12
I13
I14
I15
I16
I17
I18
I19
I20
I21
I22
I23
I24
I25
I26
I27
I28
I29
I30
I31
I11
I0
I1
I2
I3
I4
I5
I6
I7
I8
I9
Table 4. WSS Codec Indirect Registers
Table 3. WSS Codec Direct Register
Register Name
Left ADC Input Control
Right ADC Input Control
Left Aux #1 Volume
Right Aux #1Volume
Left Aux #2 Volume
Right Aux #2 Volume
Left DAC (PC Wave) Volume
Right DAC (PC Wave) Volume
Fs & Playback Data Format
Interface Configuration
Pin Control
Error Status and Initialization
MODE and ID
Monitor Loopback Volume
Playback Upper Base Count
Playback Lower Base Count
Alternate Feature Enable I
Alternate Feature Enable II
Left Line (Synthesizer) Volume
Right Line (Synthesizer) Volume
Timer Low Byte
Timer High Byte
Alternate Sample Frequency
Extended Register Access (X regs)
Alternate Feature Status
Compatibility ID
Mono Input & Output Control
Reserved
Capture Data Format
Reserved
Capture Upper Base Count
Capture Lower Base Count
Reg.
R0
R1
R2
R3
Index Address register
Indexed Data register
Status register
PIO Data register
Register Name
CS4237B
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