WM8720 Datasheet, PDF (13/15 Pages) Wolfson Microelectronics plc – 24-bit, 96kHz Stereo DACwith Volume Control

Production Data
WM8720
DAC OUTPUT CONTROL
Bits 5, 6, 7 and 8 (PL[3:0]) of register 2 are used to control the output format as shown in Table 11.
PL3
PL2
PL1
PL0
LEFT
OUTPUT
0
0
0
0
MUTE
0
0
0
1
L
0
0
1
0
R
0
0
1
1
(L + R)/2
0
1
0
0
MUTE
0
1
0
1
L
0
1
1
0
R
0
1
1
1
(L + R)/2
1
0
0
0
MUTE
1
0
0
1
L
1
0
1
0
R
1
0
1
1
(L + R)/2
1
1
0
0
MUTE
1
1
0
1
L
1
1
1
0
R
1
1
1
1
(L + R)/2
Table 11 Programmable DAC Output Format
RIGHT
OUTPUT
MUTE
MUTE
MUTE
MUTE
L
L
L
L
R
R
R
R
(L + R)/2
(L + R)/2
(L + R)/2
(L + R)/2
NOTE
Mute both channels
Reverse channels
Stereo mode
Mono mode
SERIAL PROTOCOL
Bits 0 (I²S) and 1 (LRP) of register 3 are used to control the input data format completely. A low on
bit 0 (I²S = 0) sets the format to Normal (MSB-first, right justified Japanese format), whilst a high
(I²S = 1) sets the format to I²S (Philips serial data protocol).
POLARITY OF LRCIN SELECT
Bit 1 (LRP) of register 3 is used to control the polarity of LRCIN (sample rate clock). When bit 1 is
low (LRP = 0), 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 (LRP = 1), the polarity assumption
is reversed.
INTERFACE CLOCKS AND SAMPLING RATES
Bits 6 (SF0) and 7 (SF1) of register 3 are used to control the sampling frequency, as shown in
Table 12.
SF0
SF1
0
0
0
1
1
0
1
1
Table 12 Sampling Frequencies
SAMPLING FREQUENCY
44.1 kHz group
22.05 / 44.1 / 88.2 kHz
48 kHz group
24 / 48 / 96 kHz
32 kHz group
16 / 32 / 64 kHz
Reserved
Not defined
INFINITE ZERO DETECTION
Bit 8 (IZD) in register 3 controls operation of the automute function. If IZD (Infinite Zero Detect) is
high, 1024 consecutive zero audio samples will force the output to zero. See Figure 6. Note that the
control of pin MUTE also affects automute operation. To turn off automute, pin MUTE must be held
low as well as IZD being low (default).
WOLFSON MICROELECTRONICS LTD
PD Rev 3.0 November 2000
13