WM8716 Datasheet, PDF (12/21 Pages) Wolfson Microelectronics plc – High Performance 24-bit, 192kHz Stereo DAC

WM8716
Production Data
DAC OUTPUT ATTENUATION
The level of attenuation for eight bit code X, is given by:
0.5 ∗ (X - 255) dB, 1 ≤ X ≤ 255
- ∞dB (mute),
X=0
Bit 8 in register 0 (LDL) is used to control the loading of attenuation data in B[7:0]. When LDL is set
to 0, attenuation data will be loaded into AL[7:0], but it will not affect the filter attenuation. LDR in
register 1 has the same function for right channel attenuation. Only when LDL or LDR is set to ’1’ will
the filter attenuation be updated. This permits left and right channel attenuation to be updated
simultaneously.
Attenuation level is controlled by AL[7:0] (left channel) or AR[7:0] (right channel). Attenuation levels
are given in Table 4.
X[7:0]
ATTENUATION LEVEL
00(hex)
- ∞dB (mute)
01(hex)
-127.0dB
:
:
:
:
FD(hex)
-1.0dB
FE(hex)
-0.5dB
FF(hex)
0.0dB
Table 7 Attenuation Control Level
Bit 2 in Reg3 is used to control the attenuator (ATC). When ATC is “high”, the attenuation data
loaded in program register 0 is used for both the left and the right channels. When ATC is low, the
attenuation data for each register is applied separately to left and right channels.
SOFT MUTE
MUT
(REG2, B0)
L
Soft Mute off (normal operation)
H
Soft Mute on (no output)
Table 8 Soft Mute
Setting MUT causes the attenuation to ramp from the current value down to 00. The values held in
the attenuation registers are unchanged. When MUT is reset the attenuation will ramp back up to the
previous value. The ramp rate is 128/fs s/0.5dB step.
DIGITAL DE-EMPHASIS
DEM
(REG2, B1)
L
De-emphasis off
H
De-emphasis on
Table 9 Digital De-Emphasis
DAC OPERATION ENABLE
OPE
(REG2,B2)
L
H
Normal operation
DAC output forced to bipolar zero,
irrespective of input data.
Table 10 DAC Operation Enable
WOLFSON MICROELECTRONICS LTD
PD Rev 3.1 April 2001
12