WM8746 Wolfson Microelectronics plc, WM8746 Datasheet - Page 20

• Manufacturer Part Number: WM8746
• Description: 24-bit, 192khz 6-channel Dac With Volume Control
• Manufacturer: Wolfson Microelectronics plc

WM8746
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Register bits [7:0] of L0A and R0A control the left and right channel attenuation of DAC 0. Register
bits [7:0] of L1A and R1A control the left and right channel attenuation of DAC 1. Register bits [7:0] of
L2A and R2B control the left and right channel attenuation of DAC 2. Register bits [7:0] of MASTA
are a register that can be used to control attenuation of all channels.
Table 8 shows how the attenuation levels are selected from the 8-bit words.
Table 8 Attenuation Control Levels
EXTENDED INTERFACE CONTROL
It is possible to run the WM8746 channels at different rates with the front two channels running at
twice the rate of the rear four channels. In this mode which is enabled by bit 0 of register 9, the
interface runs at the faster data rate but pin 10 (LRCIN2) acts as the framing LRCIN for the rear
channels see Figure 9.
When the WM8746 receives updates to the volume levels it will, by default, wait for the signal to pass
through the V
function ensures that minimal distortion is seen on the output when the volume is changed and is
applied separately to each channel.
DAC OUTPUT ATTENUATION
0001001
Split rate mode
0001001
Zero crossing detect
REGISTER ADDRESS
REGISTER ADDRESS
FE(hex)
FF(hex)
00(hex)
01(hex)
XA[7:0]
:
:
:
CAP
voltage level before applying the change to the output. This zero cross detect
BIT
BIT
0
1
ATTENUATION LEVEL
LABEL
LABEL
-∞dB (mute)
2SPD
ZCD
-127.5dB
-0.5dB
0dB
:
:
:
DEFAULT
DEFAULT
0
0
Activates the split rate mode
Controls the ZCD
0: Normal operation
1: Split rate operation
0: Enabled
1: Disabled
DESCRIPTION
DESCRIPTION
PD, October 2008, Rev 4.2
Production Data
20