STAC9708 Datasheet, PDF (31/56 Pages) List of Unclassifed Manufacturers – Multi-Channel AC97 Codec With Multi-Codec Option

SigmaTel, Inc.
Preliminary
STAC9708/11
for independent control of the stereo enhancement between LINE_OUT and DAC_OUT. SS3D provides
for a wider soundstage extending beyond the normal 2-speaker arrangement. Note that the 3D bit in the
general purpose register (20h) must be set to 1 to enable SS3D functionality and for the bits in 22h to
take effect.
Table 16, 17. 3D Control Registers
DP1, DP0
00
01
10
11
LINE_OUT
SEPARATION
RATIO
0 (Off)
3 (Low)
4.5 (Med)
6 (High)
DPR1, DPR0
00
01
10
11
DAC_OUT
SEPARATION
RATIO
0 (Off)
3 (Low)
4.5 (Med)
6 (High)
The three separation ratios are implemented as shown above. The separation ratio defines a series of
equations that determine the amount of depth difference (High, Medium, and Low) perceived during
two-channel playback. The ratios provide for options to narrow or widen the soundstage.
4.4.9 Multi-Channel Programming Register (Index 74h)
This read/write register is used to program the various options for multi-channel configurations. Only
the two LSBs are used (MC0 and MC1), and they define which AC-Link slot data is supplied to the
four audio DACs on the STAC9708/11. PCM2 in the table below is the surround stereo DAC, which
drives the DAC_OUT pins. The purpose of using slot 10 and 11 in the final configuration is to allow the
possibility of an eight channel architecture using two STAC9708 devices in the multi-codec
configuration. Also see “Multiple Codec Support” discussion for information on the use of external pins
CID1 and CID0.
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10/02/98