WM8951L_07 WOLFSON [Wolfson Microelectronics plc], WM8951L_07 Datasheet - Page 32

• Manufacturer Part Number: WM8951L_07
• Description: Stereo ADC with Microphone Input and Clock Generator
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM8951L
POWER DOWN MODES
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The controller will then send the remaining eight data bits (bits B7-B0) and the WM8951L will then
acknowledge again by pulling SDIN low.
A stop condition is defined when there is a low to high transition on SDIN while SCLK is high. If a
start or stop condition is detected out of sequence at any point in the data transfer then the device
will jump to the idle condition.
After receiving a complete address and data sequence the WM8951L returns to the idle state and
waits for another start condition. Each write to a register requires the complete sequence of start
condition, device address and R/W bit followed by the 16 register address and data bits.
The WM8951L contains power conservation modes in which various circuit blocks may be safely
powered down in order to conserve power. This is software programmable as shown in the table
below.
Table 20 Power Conservation Modes Software Control
The power down control can be used to either a) permanently disable functions when not required in
certain applications or b) to dynamically power up and down functions depending on the operating
mode, e.g.: during record. Please follow the special instructions below if dynamic implementations
are being used.
LINEINPD: Simultaneously powers down both the Line Inputs. This can be done dynamically without
any audible effects on the ADC. This is of use when the device enters Pause or Stop modes or the
Microphone input has been selected.
MICPD: Simultaneously powers down both the Microphone Input and Microphone Bias. If this is done
dynamically, audible pops through the ADC will result. This will only be audible if the Microphone
Input is selected to the ADC at the time. If the state of MICPD is changed then the controlling DSP or
microprocessor should switch to select the Line Inputs as input to the ADC (INSEL) before changing
MICPD. This is of use when the device enters Pause or Stop modes or the Microphone Input is not
selected.
ADCPD: Powers down the ADC and ADC Filters. If this is done dynamically then audible pops will
result if any signals were present through the ADC. To overcome this whenever the ADC is to be
powered down, either mute the Microphone Input (MUTEIN) or MUTELINEIN, then change ADCPD.
This is of use when the device enters Pause or Stop modes regardless of whether Microphone or
Line Inputs are selected.
0000110
Power Down
Control
REGISTER
ADDRESS
0
1
2
5
6
7
BIT
LINEINPD
MICPD
ADCPD
OSCPD
CLKOUTPD
POWEROFF
LABEL
DEFAULT
1
1
1
0
0
1
Line Input Power Down
1 = Enable Power Down
0 = Disable Power Down
Microphone Input an Bias
Power Down
1 = Enable Power Down
0 = Disable Power Down
ADC Power Down
1 = Enable Power Down
0 = Disable Power Down
Oscillator Power Down
1 = Enable Power Down
0 = Disable Power Down
CLKOUT power down
1 = Enable Power Down
0 = Disable Power Down
Power Off Device
1 = Device Power Off
0 = Device Power On
PD Rev 4.1 December 2007
DESCRIPTION
Production Data
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