SigmaTel, Inc.
Data Sheet
STAC9721
28
04/07/00
04/07/00
Table 19. Multi-Channel Programming Register
External
Pins
CID1, CID0
Extended
Audio ID
28h
ID1, ID0
Codec
Designation
Multi-
Channel
Selection
74h
MC1, MC0
PCM
OUT Left
PCM
OUT
Right
0, 0
Slot 3
Slot 4
0, 1
Slot 7
Slot 8
1, 0
Slot 6
Slot 9
CID1 = DVdd
or floating,
CID0 = DVdd
or floating
0, 0
Primary, 00
1, 1
Slot 10
Slot 11
0, 0
Slot 3
Slot 4
0, 1
Slot 7
Slot 8
1, 0
Slot 6
Slot 9
CID1 = DVdd
or floating,
CID0 = GND
0, 1
Secondary, 01
1, 1
Slot 10
Slot 11
0, 0
Slot 7
Slot 8
0, 1
Slot 3
Slot 4
1, 0
Slot 10
Slot 11
CID1 = GND,
CID0 = DVdd
or floating
1, 0
Secondary, 10
1, 1
Slot 6
Slot 9
0, 0
Slot 6
Slot 9
0, 1
Slot 10
Slot 11
1, 0
Slot 3
Slot 4
CID1 = GND,
CID0 = GND
1, 1
Secondary, 11
1, 1
Slot 7
Slot 8
4.4.14 Clock Access (Index 76h and 78h)
The Clock Access register (index 78h) is a locked register and can only be properly
written and read from when ABBAh has been written into register 76h.
The
STAC9744/45 can operate as a remotely located secondary without a 24.576MHz master
clock input or local crystal. The STAC9744/45 can synchronize to the BIT_CLK after a
register adjustments. The first adjustment starts the synchronization process by enabling
the ALTCLK D13, PWD CL2x D12, CLK INV D11, and OSC PWD D1 bits of register
78h. With this adjustment, the STAC9744/45 will operate remotely without the 24.576
MHz master clock signal and without a local crystal. The XTAL_IN input should be
connected to DGND with a 10k
Ω or larger resistor. The reserved bits of register 78h
should not be written to.
4.4.15 Vendor ID1 and ID2 (Index 7Ch and 7Eh)
These two registers contain four 8-bit ID codes. The first three codes have been assigned
by Microsoft using their Plug and Play Vendor ID methodology. The fourth code is a
SigmaTel, Inc. assigned code identifying the STAC9721/23. The ID1 register (index
7Ch) contains the value 8384h, which is the first (83h) and second (84h) characters of the
Microsoft ID code. The ID2 register (index 7Eh) contains the value 7609h, which is the
third (76h) of the Microsoft ID code, and 09h which is the STAC9721/23 ID code.
NOTE: The lower half of the Vendor ID2 register (index 7Eh) currently contains the
value 09h identifying the STAC9721/23. This value can be used by the audio driver, or
miniport driver in the case of WIN98, to adjust software functionality to match the
feature-set of the STAC9721/23. This portion of the register will likely contain different
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