WM8951L datasheet(32/42 Pages) WOLFSON

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WM8951L

Production Data

PD Rev 4.1 December 2007

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.

POWER DOWN MODES

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.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

LINEINPD

Line Input Power Down

1 = Enable Power Down

0 = Disable Power Down

MICPD

Microphone Input an Bias

Power Down

1 = Enable Power Down

0 = Disable Power Down

ADCPD

ADC Power Down

1 = Enable Power Down

0 = Disable Power Down

OSCPD

Oscillator Power Down

1 = Enable Power Down

0 = Disable Power Down

CLKOUTPD

CLKOUT power down

1 = Enable Power Down

0 = Disable Power Down

0000110

Power Down

Control

POWEROFF

Power Off Device

1 = Device Power Off

0 = Device Power On

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.

WM8951L Datasheet(PDF) 32 Page - Wolfson Microelectronics plc

WM8951L Datasheet(HTML) 32 Page - Wolfson Microelectronics plc

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