STAC9750 Datasheet, PDF (51/73 Pages) Integrated Device Technology – VALUE-LINE TWO-CHANNEL AC’97 CODECS

STAC9750/9751
VALUE-LINE TWO-CHANNEL AC’97 CODECS
PC AUDIO
6.5.24.
Revision Code (6Ch)
Default: 00xxh
D15
D14
D13
D12
D11
D10
D9
D8
0
0
0
0
0
0
0
0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
0
The device Revision Code register (index 6Ch) contains a software readable revision-specific code
used to identify performance, architectural, or software differences between various device revi-
sions. Bits 7:0 of the Revision Code register are user readable; bits 15:8 are not used at this time
and will return zeros when read. This value can be used by the audio driver, or miniport driver in the
case of WIN98^® WDM approaches, to adjust software functionality to match the feature-set of the
STAC9750/9751. This will allow the software driver to identify any required operational differences
between the existing STAC9750/9751 and future versions.
6.5.25.
Analog Special (6Eh)
Default: 0000h
D15
D7
RSVD
D14
D13
Reserved
D6
D5
MUTE FIX
DISABLE
ADCSLT1
D12
AC97 ALL MIX
D4
ADCSLT0
D11
D3
Reserved
D10
D9
Reserved
D2
D1
20/30 SEL SPLYOVR EN
D8
D0
SPLYOVR
VAL
The Analog Special register has several bits used to control various functions specific to the
STAC9750/9751.
6.5.25.1. ALL MIX
The AC’97 ALL_MIX, bit D12 of register 6Eh, controls the record source when the Stereo Mix option
is selected for recording. If the AC’97 mode is default logic 1, the “Stereo Mix Record” option will
include the sum of the analog sources with or without 3D enhancement, and the main PCM DAC
output. If the “ALL Analog Record” option is selected, the Stereo Mix Record option will include the
sum of the analog sources only, with or without 3D enhancement. The “AC’97 mode” is useful for
recording all sound sources. The “ALL Analog Record” mode is useful in conjunction with the POP
BYPASS mode for recording all analog sources, which are often further processed and combined
with other PCM data to be output directly to the DAC outputs which are configured in POP_BYPASS
mode using the General Purpose register (index 20h).
IDT™
VALUE-LINE TWO-CHANNEL AC’97 CODECS
51
STAC9750/9751
V 5.8 103106