WM8581SEFT Wolfson Microelectronics Ltd., WM8581SEFT Datasheet - Page 66

• Manufacturer Part Number: WM8581SEFT
• Description: Multichannel Codec with S/pdif Transceiver
• Manufacturer: Wolfson Microelectronics Ltd.

WM8581
POWERDOWN MODES
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Table 65 GPO Control Registers
GPO4
R41
29h
The WM8581 has powerdown control bits allowing specific parts of the chip to be turned off when not in use.
The ADC is powered down by setting the ADCPD register bit. The three stereo DACs each have a separate
powerdown control bit, DACPD[2:0], allowing individual stereo DACs to be powered down when not in use.
DACPD can be overwritten by setting ALLDACPD to powerdown all DACs
The S/PDIF transmitter is powered down by setting SPDIFTXD. Setting SPDIFRXD powers down the S/PDIF
receiver.
The PLL, Oscillator and S/PDIF clock recovery circuits are powered down by setting PLLPD, OSCPD and
SPDIFPD respectively.
Setting all of ADCPD, DACPD[2:0], SPDIFTXD, SPDIFRXD and OUTPD[3:0] will powerdown everything
except the references VMIDADC, ADCREF and VMIDDAC. These may be powered down by setting PWDN.
Setting PWDN will override all other powerdown control bits. It is recommended that the ADC and DAC are
powered down before setting PWDN. The default is for all powerdown bits to be set except OSCPD and
PWDN.
REGISTER ADDRESS
3:0
PWRDN 2
PWRDN 1
GPO7OP[3:0]
R51
33h
R50
32h
BIT
4:2
1
6
0
0
1
0110
DACPD[2:0]
ALLDACPD
PLLAPD
OSCPD
ADCPD
LABEL
PWDN
1001 = REC_FREQ192
1010 = ZFLAG
1011 = NON_AUDIO
1100 = CPY_N
1101 = DEEMP
1110 = Set GPO as S/PDIF input (CMOS-compatible
input). Only applicable for GPO3/4/5.
1111 = Set GPO as S/PDIF input (‘comparator’ input for
AC coupled consumer S/PDIF signals). Only applicable
for GPO3/4/5
DEFAULT
111
0
1
1
0
1
Master powerdown (overrides all
powerdown registers)
0 = All digital circuits running,
outputs are active
1 = All digital circuits in power
down mode, outputs muted
ADC powerdown
0 = ADC enabled
1 = ADC disabled
DAC powerdowns
0 = DAC enabled
1 = DAC disabled
DACPD[0] = DAC1
DACPD[1] = DAC2
DACPD[2] = DAC3
Overrides DACPD[3:0]
0 = DACs under control of
DACPD[3:0]
1= All DACs are disabled.
OSC output powerdown
0 = OSC output enabled
1 = OSC output disabled
A CMOS input can be applied to
the OSC input when powered
down.
0 = PLLA enabled
1 = PLLA disabled
DESCRIPTION
PP Rev 1.0 March 2006
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