WM8722

Advanced Information

WOLFSON MICROELECTRONICS LTD

AI Rev 1.5 May 2000

18

DAC OUTPUT CONTROL

Bits 5, 6, 7 and 8 (PL[3:0]) of register 2 are used to control the output format.

PL0

PL1

PL2

PL3

LEFT OUTPUT

RIGHT OUTPUT

NOTE

000

0

MUTE

MUTE

Mute Both Channels

000

1

MUTE

R

001

0

MUTE

L

001

1

MUTE

(L + R)/2

010

0

RMUTE

010

1

RR

011

0

R

L

Reverse Channels

011

1

R(L + R)/2

100

0

LMUTE

100

1

L

R

Stereo Mode

101

0

LL

101

1

L(L + R)/2

110

0

(L + R)/2

MUTE

110

1

(L + R)/2

R

111

0

(L + R)/2

L

111

1

(L + R)/2

(L + R)/2

Mono Mode

Table 9. Programmable Output Format

REGISTER 3

AUDIO DATA INPUT FORMAT

WM8722 allows maximum flexibility over the control of the audio data interface, allowing selection of

format type, word length, and sample rates.

DIGITAL AUDIO SERIAL PROTOCOL

A low on bit 0 sets the format to Normal (MSB-first, right justified Japanese format), whilst a high sets

the format to I

AUDIO INTERFACE CLOCKS

Bit 1 (LRP) of register 3 is used to control the polarity of LRCIN (sample rate clock). When bit 1 is

low, left channel data is assumed when LRCIN is in a high phase and right channel data is assumed

when LRCIN is in a low phase. When bit 1 is high, the polarity assumption is reversed.

ATTENUATOR CONTROL

Bit 2 in register 3 (A1[1:0] = 11) is used to control the attenuator (ATC). When ATC is high, the

attenuation data loaded in program register 0 is used for both the left and the right channels. When

ATC is low, the attenuation data for each register is applied separately to left and right channels.

REGISTER 4/5

ANALOGUE MIXER TRIM

Bits 0-4 of register 4, MTRIML[0:4], set the gain level of the first stage of analogue mixing on the left

channel. The 5-bit register selects 1.5 dB increments of the MIXINL signal, over a range of +12dB to

–34.5dB. A 6

Similarly, bits 0-4 of register 5, MTRIMR[0:4], set the attenuation level of the first stage of analogue

mixing on the right channel. The 5-bit register allows 1.5 dB increments of the MIXINR signal, over a

range of +12dB to –34.5dB. A 6