B15
R/W
B14
B13
B12
B11
B10
B9
B8
B7
B6
B5
B4
B3
B2
B1
B0
Register 7
IDX6
IDX5
IDX4
IDX3
IDX2
IDX1
IDX0
ATLD ATTS MUT6 MUT5 MUT4 MUT3 MUT2 MUT1
R/W
Read/Write Mode Select
When R/W = 0, a Write operation is performed.
When R/W = 1, a Read operation is performed.
Default Value: 0
ATLD
Attenuation Control
This bit is Read/Write.
Default Value: 0
ATLD = 0
ATLD = 1
Attenuation Control Disabled (default)
Attenuation Control Enabled
The ATLD bit must be set to logic “1” in order for the attenuators to function. Setting ATLD to logic “0” will
disable the attenuator function and cause the current attenuator data to be lost.
Set ATLD = 1 immediately after reset.
ATTS
Attenuation Rate Select
This bit is Read/Write.
Default Value: 0
ATTS = 0
ATTS = 1
Attenuation rate is 2/fS (default)
Attenuation rate is 4/fS
Changes in attenuator levels are made by incrementing or decrementing the attenuator by one step (0.5dB) for
every 2/fS or 4/fS time interval until the programmed attenuator setting is reached. This helps to minimize
audible ‘clicking’, or zipper noise, while the attenuator is changing levels. The ATTS bit allows you to select
the rate at which the attenuator is decremented/incremented during level transitions.
MUTx
Soft Mute Control
where x = 1-6, corresponding to the DAC output VOUTx.
These bits are Read/Write.
Default Value: 0
MUTx = 0
MUTx = 1
Mute Disabled (default)
Mute Enabled
The mute bits, MUT1 through MUT6, are used to enable or disable the Soft Mute function for the
corresponding DAC outputs, VOUT1 through VOUT6. 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 will be decremented
from the current setting to the infinite attenuation setting one attenuator step (0.5dB) at a time, with the rate
of change programmed by the ATTS bit. This provides a quiet, ‘pop’ free muting of the DAC output. Upon
returning from Soft Mute, by setting MUTx = 0, the attenuator will be incremented one step at a time to
the previously programmed attenuator level.
®
17
PCM1600, PCM1601
BB [ BURR-BROWN CORPORATION ]
