STA304A

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12.0 REGISTER SUMMARY

12.1 Reset Register (add. 00h)

Writing any value to this register performs a register reset, which causes all registers to revert to their default

values. Reading this register returns 00E4h as it is the ID code of the part and its 3D Stereo Enhancement type

(See AC'97 revision 2.1 specification, section 6.3.1).

12.2 LR Volume Register (add. 02h)

This register manage the stereo (both right and left channels) output signal volumes. The MSB of the register

is the mute bit. When this bit is set to 1 the level for that channel is set at -

∞ dB. ML6 through ML0 is for the left

channel level, MR6 through MR0 is for the right channel.

There are two options: in 'Full Compliance' operating mode (bit 0 in the CRA register, address 5Ah, is set to '0')

only 6 bits are active (Mx0 to Mx5) and each step corresponds to 1.5 dB. In 'Proprietary' mode (bit 0 in the CRA

register is set to '1') Mx0 to Mx6 can have the values between 0h to 68h (110 1000) and each step corresponds

to 1dB. Greater values are undefined.

The default value is 8000h (1000 0000 0000 0000), which corresponds to 0 dB attenuation with mute on.

'Full Compliance' Mode

'Proprietary' Mode

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

0

000

000

01

110

01

0

0

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

Mute

ML6

ML5

ML4

ML3

ML2

ML1

ML0

X

MR6

MR5

MR4

MR3

MR2

MR1

MR0

Mute

Mx6…Mx0

Function

0

x00 0000

0 dB Attenuation

0

x01 1111

46.5dB Attenuation

0

x11 1111

94.5dB Attenuation

1

xxx xxxx

∞ dB Attenuation

Mute

Mx6…Mx0

Function

0

000 0000

0 dB Attenuation

0

001 1111

31dB Attenuation

0

011 1111

63dB Attenuation

…...

0

110 0001

97dB Attenuation

0

110 0010

99dB Attenuation

0

110 0011

100dB Attenuation

0

110 0100

102dB Attenuation

0

110 0101

104dB Attenuation

0

110 0110

107dB Attenuation

0

110 0111

111dB Attenuation

0

110 1000

∞ dB Attenuation

1

xxx xxxx

∞ dB Attenuation