Audio Codec '97

AC ‘97 Component Specification Revision 2.3 Rev 1.0
50
Mute Mx5...Mx0 Function Range
0 00 0000 0 dB Attenuation Req.
0 01 1111 46.5 dB Attenuation Req.
0 11 1111 94.5 dB Attenuation Optional
1 xx xxxx ∞ dB Attenuation Req.
Table 19. Master, Aux Out, and Mono Volume
5.7.3 Master Tone Control Registers (Index 08h)
Reg Name D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Default
08h Master Tone X X X X BA3 BA2 BA1 BA0 X X X X TR3 TR2 TR1 TR0 0F0Fh
Optional register for support of tone controls (bass and treble). If the part does not support bass and treble, writing
to this register will have no effect and reading will result in all zeroes. The step size is 3 dB with optional support
for 1.5 dB. The step size option is accomplished by either using 3 bits (MSB justified) for 3 dB steps or all 4 bits for
1.5 dB steps. Writing a 0000h corresponds to +10.5 dB of gain. Center frequencies (from which gains are
measured) are 100 Hz for Bass and 10 kHz for Treble. The default value is 0F0Fh, which corresponds to bypass of
bass or treble gain.
TR3...TR0
or
BA3...BA0
Support
Required
Function
0000 yes +10.5 dB of gain
0001 no +9 dB of gain
0010 yes +7.5 dB of gain
0011 no +6 dB of gain
.. ...
0110 yes +1.5 dB of gain
0111 yes 0 dB of gain
1000 yes -1.5 dB of gain
.. ...
1100 yes -7.5 dB
1101 no -9 dB of gain
1110 yes -10.5 dB of gain
1111 yes Bypass
Table 20. Tone Control