CS4235 Datasheet, PDF (54/94 Pages) Cirrus Logic – CrystalClear Low Cost ISA Audio System

CS4235
CrystalClear ^TM Low Cost ISA Audio System
Reset
SBbase+6, write only
When bit D[0] of this register is set to a one and
then set to a zero, a reset of the Sound Blaster
interface will occur.
Read Data Port
SBbase+A, read only
When bit D[7] of the Data Available Register,
SBbase+E, is set =1 then valid data is available
in this register. The data may be the result of a
Command that was previously written to the
Command/Write Data Register or digital audio
data.
Command/Write Data
SBbase+C, write only
The Command/Write Data register is used to
send Sound Blaster Pro commands.
Write Buffer Status,
SBbase+C, read only
The Write Buffer Status register bit D[7] indi-
cates when the SBPro interface is ready to
accept another command to the Command/Write
Data register. D[7]=1 indicates ready. D[7]=0 in-
dicates not ready.
Sound Blaster Mixer Registers
The Sound Blaster mixer registers are shown in
Table 15.
Reset Register,
Mixer Index 00H
Writing any value to this register will reset the
mixer to default values.
Voice Volume Register,
Mixer Index 04H, Default = 99H
This register provides 8 steps of voice volume
control each for the right and left channels.
Microphone Mixing Register,
Mixer Index 0AH, Default = 01H
This register provides 4 steps of microphone vol-
ume control.
Register
00H
02H
04H
06H
08H
0AH
0CH
0EH
20H
22H
24H
26H
28H
2AH
2CH
2EH
54
D7
D6
D5
D4
D3
D2
D1
D0
DATA RESET
RESERVED
VOICE VOLUME LEFT
VOICE VOLUME RIGHT
RESERVED
RESERVED
X
X
X
X
X
MIC MIXING
X
X
X
INPUT SELECT
X
X
X
X
X
X
X
VSTC
X
RESERVED
MASTER VOLUME LEFT
MASTER VOLUME RIGHT
RESERVED
FM VOLUME LEFT
FM VOLUME RIGHT
CD VOLUME LEFT
CD VOLUME RIGHT
RESERVED
RESERVED
LINE VOLUME LEFT
LINE VOLUME RIGHT
Table 15. SBPro Compatible Mixer Interface
DS252PP2