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WM8777
OUTPUT SELECT AND ENABLE CONTROL
Register bits MX1[2:0] to MX4[2:0] control the output select. The output select block consists of a
summing stage and an input select switch for each input allowing each signal to be output
individually or summed with other signals and output on each analogue output. The default for all
outputs is DAC playback only. VOUT1/2/3 may be selected to output DAC playback, AUX, analogue
bypass or a sum of these using the output select controls MX1/2/3[2:0]. VOUT4 may be selected to
output DAC playback, analogue bypass or a sum of these signals using MX4[1:0]. It is recommended
that bypass is not selected for output on more than two stereo channels simultaneously to avoid
overloading the input buffer, resulting in a decrease in performance.
The output mixers and PGAs can be powered down under control of OUTPD1/2/3/4. Each stereo
channel may be powered down separately. Setting OUTPD1/2/3/4 will power off the mixer and PGA
and switch the analogue outputs VOUTL/R to VMIDDAC to maintain a dc level on the output.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
(32h)
001
VOUT1 Output select (see Figure 28)
2:0
5:3
2:0
4:3
MX1[2:0]
MX2[2:0]
MX3[2:0]
MX4[1:0]
Output Mux
and
Powerdown
Control 1
(DAC playback)
001
VOUT2 Output select (see Figure 28)
VOUT3 Output select (see Figure 28)
(DAC playback)
(33h)
001
Output Mux
and
Powerdown
Control 2
(DAC playback)
01
VOUT4 Output select (see Figure 29)
(DAC playback)
Table 66 Output Mux Register
Figure 28 MX1/2/3[2:0] Output Select
Figure 29 MX4[1:0] Output Select
PP Rev 1.94 November 2004
65
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
