Datasheet
PCM1753
PCM1754
PCM1755
SLES092C – OCTOBER 2003 – REVISED FEBRUARY 2009
www.ti.com
20
Register Definitions
B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0
Register 16 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 AT17 AT16 AT15 AT14 AT13 AT12 AT11 AT10
B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0
Register 17
0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 AT27 AT26 AT25 AT24 AT23 AT22 AT21 AT20
ATx[7:0]: Digital Attenuation Level Setting
Where x = 1 or 2, corresponding to the DAC output V
OUT
L (x = 1) and V
OUT
R (x = 2).
Default value: 1111 1111b
Each DAC channel (V
OUT
L and V
OUT
R) includes a digital attenuation function. The attenuation level can be
set from 0 dB to –63 dB in 0.5-dB steps. Changes in attenuator levels are made by incrementing or
decrementing one step (0.5 dB) for every 8/f
S
time internal until the programmed attenuator setting is reached.
Alternatively, the attenuation level can be set to infinite attenuation (or mute).
The attenuation data for each channel can be set individually. The attenuation level is set using the following
formula:
Attenuation level (dB) = 0.5 × (ATx[7:0]
DEC
– 255)
where ATx[7:0]
DEC
= 0 through 255.
For ATx[7:0]
DEC
= 0 through 128, attenuation is set to infinite attenuation.
The following table shows the attenuation levels for various settings:
ATx[7:0] DECIMAL VALUE ATTENUATION LEVEL SETTING
1111 1111b 255 0 dB, No Attenuation. (default)
1111 1110b 254 –0.5 dB
1111 1101b 253 –1.0 dB
L LL
1000 0011b 131 –62.0 dB
1000 0010b 130 –62.5 dB
1000 0001b 129 –63.0 dB
1000 0000b 128 Mute
L LL
0000 0000
B
0 Mute
B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0
Register 18
0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 SRST OVER RSV RSV RSV RSV MUT2 MUT1
MUTx: Soft Mute Control
where x = 1 or 2, corresponding to the DAC outputs V
OUT
L (x = 1) and V
OUT
R (x = 2).
Default value: 0
MUTx = 0
Mute disabled (default)
MUTx = 1 Mute enabled
The mute bits, MUT1 and MUT2, are used to enable or disable the soft mute function for the corresponding
DAC outputs, V
OUT
L and V
OUT
R. The soft mute function is incorporated into the digital attenuators. When mute
is disabled (MUTx = 0), the attenuator and DAC operate normally. When mute is enabled by setting MUTx = 1,
the digital attenuator for the corresponding output is decreased from the current setting to infinite attenuation,
one attenuator step (0.5 dB) for every 8/f
S
seconds. This provides pop-free muting of the DAC output.