Audio Codec '97

AC ‘97 Component Specification Revision 2.3 Rev 1.0
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SE4...SE0 3D Stereo Enhancement Technique SE4...SE0 3D Stereo Enhancement Technique
00000 (0) No 3D Stereo Enhancement 10000 (16) Harman International
00001 (1) Analog Devices 10001 (17) Nvidia
00010 (2) Creative Technology 10010 (18) Philips
00011 (3) National Semiconductor 10011 (19) Texas Instruments
00100 (4) Yamaha 10100 (20) VLSI Technology
00101 (5) BBE Sound 10101 (21) TriTech
00110 (6) Crystal Semiconductor 10110 (22) Realtek
00111 (7) Qsound Labs 10111 (23) Samsung
01000 (8) Spatializer Audio Laboratories 11000 (24) Wolfson Microelectronics
01001 (9) SRS Labs 11001 (25) Delta Integration
01010 (10) Platform Tech 11010 (26) SigmaTel
01011 (11) AKM Semiconductor 11011 (27) KS Waves
01100 (12) Aureal 11100 (28) Rockwell
01101 (13) Aztech Labs 11101 (29) Reserved
01110 (14) Binaura 11110 (30) Reserved
01111 (15) ESS Technology 11111 (31) Reserved
Table 18. 3D Stereo Enhancement Vendor IDs
5.7.2 Play Master Volume Registers (Index 02h, 04h and 06h)
Reg Name D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Default
02h Master Volume Mute X ML5 ML4 ML3 ML2 ML1 ML0 X X MR5 MR4 MR3 MR2 MR1 MR0 8000h
04h Aux Out Volume Mute X ML5 ML4 ML3 ML2 ML1 ML0 X X MR5 MR4 MR3 MR2 MR1 MR0 8000h
06h Mono Volume Mute X X X X X X X X X MM5 MM4 MM3 MM2 MM1 MM0 8000h
Register 02h controls the stereo master volume (both left and right channels).
Register 04h controls the optional AUX_OUT volume (AUX_OUT can be implemented as LNLVL_OUT,
HP_OUT, or 4CH_OUT
 see Section 5.2.1). If Aux Out Volume (Register 04h) default value (following cold or
warm reset) reads 0000h, then the optional volume control is not supported. Note that the AUX_OUT may be
powered down through bit PR6 in Register 26h.
Register 06h controls the optional MONO_OUT.
For all of these registers each step corresponds to 1.5 dB. The MSB of the register is the mute bit. When this bit is
set to 1 the level for that channel is set at -
∞ dB. ML5 through ML0 is for the left channel level, MR5 through MR0
is for the right channel and MM5 through MM0 is for the mono out channel.
Support for the MSB of the level is optional.
If the MSB is not supported then AC ‘97 needs to detect when that
bit is set and set all four LSBs to 1s.
Example: If AC ‘97 only supports 5 bits of resolution in its mixer and the
driver writes a 1xxxxx, then AC ‘97 must interpret that as x11111. It will also respond when read with x11111
rather then 1xxxxx (the original value). The driver can use this feature to detect if support for the 6th bit is there or
not.
The default value is 8000h (1000 0000 0000 0000), which corresponds to 0 dB attenuation with mute on.