YMF740C Datasheet, PDF (29/44 Pages) List of Unclassifed Manufacturers – DS-1L

YMF740C
2-2-2. Sound Blaster Pro Mixer
The following shows the register map of the Mixer section of Sound Blaster Pro.
Address
00h
04h
0Ah
0Ch
0Eh
22h
26h
28h
2Eh
F0h
F1h
F8h
b7
b6
b5
Voice Volume L
-
-
-
-
-
Ifilter*
-
- Ofilter*
Master Volume L
MIDI Volume L
CD Volume L*
Line Volume L*
SBPDA -
-
-
-
-
b4
b3
b2
b1
b0
Reset
"1"
Voice Volume R
"1"
"1"
-
MIC Volume*
"1"
Input Source*
"1"
"1"
-
- St. SW "1"
"1"
Master Volume R
"1"
"1"
MIDI Volume R
"1"
"1"
CD Volume R*
"1"
"1"
Line Volume R*
"1"
-
SS
SM
SE SBPDR
SCAN DATA
-
-
-
-
SBI
Remark
SB Pro Mixer
Suspend / Resume
IRQ Status
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.
(1) SB Mixer ® DSP
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.
January 14, 1999
-29-