WM8991 datasheet(131/174 Pages) WOLFSON

131 / 174 page

Pre-Production

WM8991

PP, May 2008, Rev 3.1

131

POWER MANAGEMENT

POWER MANAGEMENT REGISTERS

The WM8991 has three control registers that allow users to select which functions are active. For

minimum power consumption, unused functions should be disabled. To minimise pop or click noise,

it is important to enable or disable functions in the correct order. See “Pop Suppression Control” for

further details of recommended control sequences.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

SPK_ENA

(rw)

SPKMIX Mixer, Speaker PGA and Speaker

Output Enable

0 = disabled

1 = enabled

OUT3_ENA

(rw)

OUT3 and OUT3MIX Enable

0 = disabled

1 = enabled

OUT4_ENA

(rw)

OUT4 and OUT4MIX Enable

0 = disabled

1 = enabled

LOUT_ENA

(rw)

LOUT (Left Headphone Output) Enable

0 = disabled

1 = enabled

ROUT_ENA

(rw)

ROUT (Right Headphone Output) Enable

0 = disabled

1 = enabled

MICBIAS_ENA

(rw)

MICBIAS Enable

0 = OFF (high impedance output)

1 = ON

2:1

VMID_MODE

[1:0]

(rw)

00b

Vmid Divider Enable and Select

00 = Vmid disabled (for OFF mode)

01 = 2 x 50k

Ω divider (Normal mode)

10 = 2 x 250k

Ω divider (Standby mode)

11 = 2 x 5k

Ω divider (for fast start-up)

R1 (1h)

VREF_ENA

(rw)

VREF Enable (Bias for all analogue

functions)

0 = VREF bias disabled

1 = VREF bias enabled

PLL_ENA

(rw)

PLL Enable

0 = disabled

1 = enabled

TSHUT_ENA

(rw)

Thermal Sensor Enable

0 = Thermal sensor disabled

1 = Thermal sensor enabled

TSHUT_OPDIS

(rw)

Thermal Shutdown Enable

(Requires thermal sensor to be enabled)

0 = Thermal shutdown disabled

1 = Thermal shutdown enabled

OPCLK_ENA

(rw)

GPIO Clock Output Enable

0 = disabled

1 = enabled

R2 (02h)

AINL_ENA

(rw)

Left Input Path Enable

(Enables AINLMUX, INMIXL, DIFFINL and

RXVOICE input to AINLMUX)

0 = disabled

1 = enabled

WM8991 Datasheet(PDF) 131 Page - Wolfson Microelectronics plc

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