ymf740c ETC-unknow, ymf740c Datasheet - Page 29

• Manufacturer Part Number: ymf740c
• Description: Ds-1l
• Manufacturer: ETC-unknow

YMF740C
2-2-2. Sound Blaster Pro Mixer
(1) SB Mixer ® DSP
The following shows the register map of the Mixer section of Sound Blaster Pro.
The registers marked with * exist, but do not function.
DS-1L does not have the circuit that corresponds to the SB Mixer. Therefore, the volume settings on the
SB Mixer are converted to the DSP coefficients of DS-1L or to AC’97 register values.
The conversion for each case is described below.
The volume of master, MIDI and Voice, are applied to this case.
When the SB register is set, a 14-bit coefficient value is determined from the following conversion table
and used as the DSP coefficient. The attenuation value of Master Volume, MIDI, and voice are summed
together to obtain the coefficient.
These volumes cannot be controlled from PCI Audio block.
Address
0Ch
0Ah
0Eh
2Eh
F0h
F1h
F8h
00h
04h
22h
26h
28h
SBPDA
b7
-
-
-
-
Master Volume L
Voice Volume L
Line Volume L*
MIDI Volume L
CD Volume L*
b6
-
-
-
-
-
Ofilter*
Ifilter*
b5
-
-
-
SCAN DATA
"1"
"1"
"1"
"1"
"1"
"1"
"1"
"1"
b4
-
-
Reset
SS
-29-
b3
-
-
-
Master Volume R
Voice Volume R
Line Volume R*
MIDI Volume R
CD Volume R*
Input Source*
SM
b2
-
-
MIC Volume*
St. SW
SE
b1
-
SBPDR
SBI
"1"
"1"
"1"
"1"
"1"
"1"
"1"
b0
Suspend / Resume
SB Pro Mixer
IRQ Status
Remark
January 14, 1999