CS5535 datasheet(239/555 Pages) NSC

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ACC Register Descriptions (Continued)

5.3.2.4

Codec Control Register (ACC_CODEC_CNTL)

Note:

Since this register could potentially be accessed by both an audio driver and a modem driver running at the same

time, it is expected that all writes occur as atomic read-modify-write accesses.

STS_NEW

Codec Status New (Read to Clear). Indicates if the status data in bits [15:0] is new:

0: Not new.

1: New.

This bit is set by hardware after receiving valid codec status data in slot 2 of the input

stream. Upon issuing a read to the codec registers, software should wait for this flag to

indicate that the corresponding data has been returned.

RSVD

Reserved. Reads return 0.

15:0

STS_DATA

Codec Status Data (Read Only). This is the codec status data that is received from

the codec in slot 2, bits [19:4] of the serial input stream. This is used for reading the

contents of registers inside the AC97 codec.

ACC I/O Offset

0Ch

Type

R/W

Reset Value

00000000h

ACC_CODEC_CNTL Register Map

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9876543210

CMD_ADD

COMM

_SEL

CMD_DATA

ACC_CODEC_CNTL Bit Descriptions

Bit

Name

Description

RW_CMD

Codec Read/Write Command. This bit specifies a read or write operation targeting the

AC97 codec’s registers.

0: Write.

1: Read.

This bit determines whether slot 1, bit 19 of the serial output stream will be high or low.

30:24

CMD_ADD

Codec Command Address. Address of the codec control register for which the com-

mand is being sent. This address goes in slot 1, bits [18:12] of the serial output stream.

This is used for specifying the address of a register in the AC97 codec (for reading or

writing).

23:22

COMM_SEL

Audio Codec Communication. Selects which codec to communicate with (for register

reads/writes):

00: Codec 1 (Primary)

01: Codec 2 (Secondary)

10: Codec 3

11: Codec 4

These bits determine output slot 0, bits [1:0]. When these bits are non-zero, bits [14:13]

of output slot 0 must be set to zeros regardless of the validity of slot 1 and slot 2.

ACC_CODEC_STATUS Bit Descriptions (Continued)

Bit

Name

Description

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