SigmaTel, Inc.
Data Sheet
STAC9721
If the current command port operation is a read then the entire slot time must be stuffed
with 0's by the AC'97 controller.
3.1.1.3 Slot 3: PCM Playback Left Channel
Audio output frame slot 3 is the composite digital audio left playback stream. In a typical
“Games Compatible" PC this slot is composed of standard PCM (.wav) output samples
digitally mixed (by the AC'97 controller or host processor) with music synthesis output
samples. If a sample stream of resolution less than 20-bits is transferred, the AC'97
controller must stuff all trailing non-valid bit positions within this time slot with 0's.
Please refer to the register programming section for details on the multi-channel
programming options.
3.1.1.4 Slot 4: PCM Playback Right Channel
Audio output frame slot 4 is the composite digital audio right playback stream. In a
typical “Games Compatible" PC this slot is composed of standard PCM (.wav) output
samples digitally mixed (by the AC'97 controller or host processor) with music synthesis
output samples. If a sample stream of resolution less than 20-bits is transferred, the
AC'97 controller must stuff all trailing non-valid bit positions within this time slot with
0's. Please refer to the register programming section for details on the multi-channel
programming options.
3.1.1.5 Slot 5: Reserved
Audio output frame slot 5 is reserved for modem operation and is not used by the
STAC9721/23.
3.1.1.6 Slot 6: PCM Center Channel
Audio output frame slot 6 is the composite digital audio center stream used in a multi-
channel application where the STAC9721/23 has been programmed to accept the DAC
PCM data from slots 6 and 9. Please refer to the register programming section for details
on the multi-channel programming options.
3.1.1.7 Slot 7: PCM Left Surround Channel
Audio output frame slot 7 is the composite digital audio left surround stream used in a
multi-channel application where the STAC9721/23 has been programmed to accept the
DAC PCM data from slots 7 and 8. Please refer to the register programming section for
details on the multi-channel programming options.
3.1.1.8 Slot 8: PCM Right Surround Channel
Audio output frame slot 8 is the composite digital audio right surround stream used in a
multi-channel application where the STAC9721/23 has been programmed to accept the
DAC PCM data from slots 7 and 8. Please refer to the register programming section for
details on the multi-channel programming options.
14
04/07/00
04/07/00
ETC [ ETC ]
