cs4237b Cirrus Logic, Inc., cs4237b Datasheet - Page 48

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

WSS EXTENDED REGISTERS
The Windows Sound System codec contains
three sets of registers: R0-R3, I0-I31, and X0-
X25. R0-R3 are directly mapped to the ISA bus
through WSSbase+0 through WSSbase+3 re-
spectively. R0 and R1 provide access to the
indirect registers I0-I31. The third set of registers
are extended registers X0-X25 that are indirectly
mapped through the WSS register I23. I23 acts
as both the extended address and extended data
register. These extended registers are only avail-
able when in MODE 3.
Accessing the X registers requires writing the
register address to I23 with XRAE set. When
XRAE is set, I23 changes from an address regis-
ter to a data register. Subsequent accesses to I23
access the extended data register. To convert I23
back to the extended address register, R0 must
be written which internally clears XRAE. As-
suming the part is in MODE 3, the following
steps access the X registers:
To read/write a different X register:
48
1. Write 17h to R0 (to access I23).
2. Write the desired X register address to R1
3. Write/Read X register data from R1.
4. Write 17h to R0 again. (resets XRAE)
5. Write the new X register address to R1
6. Read/Write new X register data from R1.
R1 is now the extended address register.
with XRAE = 1.
R1 is now the extended data register.
R1 is now the extended address register.
with XRAE = 1.
R1 is now the new extended data register.
Extended Register Access (I23)
XA3
D7
X18-X24
WSSbase+0
WSSbase+1
Index
X10
X11
X12
X13
X14
X15
X16
X17
X25
Address
X0
X1
X2
X3
X4
X5
X6
X7
X8
X9
Table 16. WSS Extended Register Control
XA2
D6
Table 17. WSS Extended Registers
XA1
D5
Register Name
Left LINE Alternate Volume
Right LINE Alternate Volume
Left MIC Volume
Right MIC Volume
Synthesis and Input Mixer Control
Right Input Mixer Control
Left FM Synthesis Volume
Right FM Synthesis Volume
Left DSP Serial Port Volume
Right DSP Serial Port Volume
Right Loopback Monitor Volume
DAC Mute and IFSE Enable
Independent ADC Sample Freq.
Independent DAC Sample Freq.
Left Master Digital Audio Volume
Right Master Digital Audio Volume
Left Wavetable Serial Port Volume
Right Wavetable Serial Port Volume
Reserved
Chip Version and ID
Reg.
XA0
D4
R1
I23
R0
XRAE
D3
Reset Address
Address/Data access
Indexed Address/Data
Register Name
XA4
D2
CS4237B
D1
res
DS213PP4
ACF
D0