STAC9704 Datasheet, PDF (18/49 Pages) Hynix Semiconductor – Multimedia Audio Codec for AC97

SigmaTel, Inc.
STAC9704/7
SYNC
BIT_CLK
Figure 9: Start of an Audio Input Frame
STAC9704 samples SYNC assertion here
STAC9704 samples first SDATA_OUT bit of frame here
SDATA_IN
Codec
Ready
slot1
slot2
End of previous audio frame
SDATA_IN's composite stream is MSB justified (MSB first) with all non-valid bit positions (for
assigned and/or unassigned time slots) stuffed with 0's by STAC9704/7. SDATA_IN data is sampled on
the falling edges of BIT_CLK.
3.1.2.1 Slot 1: Status Address Port
The status port is used to monitor status for STAC9704/7 functions including, but not limited
to, mixer settings, and power management.
Audio input frame slot 1’s stream echoes the control register index, for historical reference,
for the data to be returned in slot 2. (Assuming that slots 1 and 2 had been tagged “valid” by
STAC9704/7 during slot 0)
Status Address Port hit assignments:
Bit (19) RESERVED
(Stuffed with 0)
Bit (18;12) Control Register Index (Echo of register index for which data is being returned)
Bit (11:0) RESERVED
(Stuffed with 0's)
The first bit (MSB) generated by STAC9704/7 is always stuffed with a 0. The following 7 bit
positions communicate the associated control register address, and the trailing 12 bit positions
are stuffed with 0's by STAC9704/7.
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10/02/98