WM8731 / WM8731L
Production Data
The exact sample rates achieved are defined by the relationships in Table 19 below.
TARGET
ACTUAL SAMPLING RATE
SAMPLING
RATE
BOSR=0
MCLK=11.2896
kHz
BOSR=1
MCLK=12.288
MCLK=18.432
kHz
MCLK=16.9344
kHz
kHz
kHz
8
8
8.018
8
8.018
(12.288MHz/256) x 1/6
32
(11.2896MHz/256) x 2/11
(18.432MHz/384) x 1/6
32
(16.9344MHz/384) x 2/11
32
44.1
48
not available
not available
(12.288MHz/256) x 2/3
not available
(18.432MHz/384) x 2/3
not available
44.1
44.1
11.2896MHz/256
16.9344MHz /384
48
not available
48
not available
12.288MHz/256
not available
18.432MHz/384
not available
88.2
96
88.2
88.2
(11.2896MHz/256) x 2
not available
(16.9344MHz /384) x 2
not available
96
96
(12.288MHz/256) x 2
(18.432MHz/384) x 2
Table 19 Normal Mode Actual Sample Rates
128/192fs NORMAL MODE
The Normal Mode sample rates are designed for standard 256fs and 384fs MCLK rates. However the
WM8731/L is also capable of being clocked from a 128 or 192fs MCLK for application over limited
sampling rates as shown in the table below.
SAMPLING
RATE
MCLK
FREQUENCY
SAMPLE
RATE
REGISTER SETTINGS
DIGITAL
FILTER
TYPE
ADC
DAC
kHz
kHz
MHz
BOSR
SR3
SR2
SR1
SR0
48
48
6.144
9.216
0
1
0
1
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
44.1
44.1
5.6448
8.4672
Table 20 128fs Normal Mode Sample Rate Look-up Table
512/768fs NORMAL MODE
512 fs and 768 fs MCLK rates can be accommodated by using the CLKIDIV2 bit (Register 8, bit 6).
The core clock to the DSP will be divided by 2 so an external 512/768 fs MCLK will become 256/384
fs internally and the device otherwise operates as in Table 18 but with MCLK at twice the specified
rate. See Table 17 for software control.
PD, Rev 4.8, April 2009
43
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
