AD1981B Analog Devices, AD1981B Datasheet - Page 20

• Manufacturer Part Number: AD1981B
• Description: AD1981B AC'97 SoundMAX® Codec
• Manufacturer: Analog Devices

AD1981B
PRO
/AUD
COPY
PRE
CC[6:0]
L
SPSR[1:0]
V
Register 60h is a read/write register that controls the equalizer functionality and data setup. This register also contains the Biquad and Coefficient Address pointer,
which is used in conjunction with the EQ Data Register (78h) to set up the equalizer coefficients. The reset default disables the equalizer function until the coefficients
can be properly set up by the software and sets the Symmetry bit to allow equal coefficients for left and right channels. All registers not shown and bits containing an X
are assumed to be reserved.
Reg
No. Name
60h EQ CTRL EQM
D15
Professional. “1” indicates professional use of channel status.
“0” indicates consumer.
Non-Audio. “1” indicates data is non-PCM format.
“0” data is PCM.
Copyright. “1” indicates copyright is asserted.
“0” copyright is not asserted.
Pre-Emphasis. “1” indicates filter pre-emphasis is 50 µs/15 µs.
“0” pre-emphasis is none.
Category Code. Programmed according to IEC standards, or as appropriate.
Generation Level. Programmed according to IEC standards, or as appropriate.
SPDIF Transmit Sample Rate.
SPSR[1:0] = 00 transmit sample rate = 44.1 kHz.
SPSR[1:0] = 01 Reserved.
SPSR[1:0] = 10 transmit sample rate = 48 kHz (reset default).
SPSR[1:0] = 11 not supported.
Validity. This bit affects the Validity flag (Bit 28 transmitted in each SPDIF L/R subframe) and enables the
SPDIF transmitter to maintain connection during error or mute conditions.
V = 1 Each SPDIF subframe (L + R) has Bit 28 set to “1.” This tags both samples as invalid.
V = 0 Each SPDIF subframe (L + R) has Bit 28 set to “0” for valid data and “1” for invalid data (error condition).
Note that when V = 0, asserting the VFORCE bit (D15) in Register 2Ah (Ext’d Audio Stat/Ctrl) will force the
Validity flag low, marking both samples as valid.
D14
MAD
LBEN
D13
X
D12
X
D11
X
EQ Control Register (Index 60h)
D10
X
D9
X
–20–
D8
X
D7
SYM CHS
D6
D5
BCA5 BCA4 BCA3 BCA2 BCA1 BCA0 8080h
D4
D3
D2
D1
D0
REV. A
Default