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YMF744B
February 3, 1999
-38-
2-2-2. Sound Blaster Pro Mixer
The following shows the register map of the Mixer section of Sound Blaster Pro.
Addressb7b6b5b4b3b2b1b0 Remark
00h Reset
04h Voice Volume L "1" Voice Volume R "1"
0Ah - - - "1" - MIC Volume*
0Ch - -
Ifilter*
"1"
Input Source*
"1"
0Eh - - Ofilter* "1" - - St. SW "1"
22h Master Volume L "1" Master Volume R "1"
26h MIDI Volume L "1" MIDI Volume R "1"
28h CD Volume L* "1" CD Volume R* "1"
2Eh Line Volume L* "1" Line Volume R* "1"
SB Pro Mixer
F0h SBPDA - - - SS SM SE SBPDR
F1h SCAN DATA
Suspend / Resume
F8h - - - - - - - SBI IRQ Status
The registers marked with * exist, but do not function.
DS-1S 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-1S 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.