Audio Codec '97

AC ‘97 Component Specification Revision 2.3 Rev 1.0
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5.9.2.1 Function Select Register (Index 66h)
Bit Default Function
FC[3:0] 0h Function Code bits
These bits specify the type of audio function described by this page. The codec
must provide information in this register.
00h – DAC 1 (Master Out)
01h – DAC 2 (AUX Out)
02h – DAC 3 (C/LFE)
03h - S/P-DIF out
04h – Phone In
05h – Mic 1 (Mic Select = 0)
06h – Mic 2 (Mic Select = 1)
07h – Line In
08h – CD In
09h – Video In
0Ah – Aux In
0Bh – Mono out
0C - 0Fh – Reserved
These bits are Read/Write and represent current AC ’97 2.2 defined I/O
capabilities. S/W will program the corresponding I/O number in this field together
with the Ring/Tip selector bit below T/R. Once S/W program the value and
properly read it back to confirm selection and implementation, it will access the
rest of the bits fields in the descriptor. A read-only value of zero in this register,
along with a read only value of zero in the IV bit, indicates that the codec does not
support the Information and I/O register.
T/R 0 Tip or Ring selection Bit.
This bit sets which jack conductor the sense value is measured from. S/W will
program the corresponding the Ring/Tip selector bit together with the I/O
number in bits FC[3:0]. Once S/W program the value and properly read it back
to confirm selection and implementation, it will access the rest of the bits fields
in the descriptor.
0 – Tip
1 – Ring
Mono inputs and outputs should report the relevant Function and Sense
information when T/R is set to ‘0’ (Tip). The FIP bit should report ‘0’ (Page 01h,
register 68h, bit 0 reports No Function Information Present) when T/R is set to a
‘1’ on a mono input or output.
5.9.2.2 Information and I/O Register (Index 68h)