WM8711 Wolfson Microelectronics Ltd., WM8711 Datasheet - Page 24

• Manufacturer Part Number: WM8711
• Description: Internet Audio DAC With Integrated Headphone Driver
• Manufacturer: Wolfson Microelectronics Ltd.

WM8711
WOLFSON MICROELECTRONICS LTD
USB MODE SAMPLE RATES
In USB mode the MCLK input is 12MHz only.
Table 14 USB Mode Sample Rate Look-Up Table
Notes:
1.
2.
3.
4.
The BOSR bit represents the base over-sampling rate. This is the rate that the WM8711 digital signal
processing is carried out at and the sampling rate will always be a sub-multiple of this. In USB mode,
with BOSR = 0, the base over-sampling rate is defined at 250Fs, with BOSR = 1, the base over-
sampling rate is defined at 272Fs. This can be used to determine the actual audio sampling rate
required by the DAC.
The exact sample rates supported for all combinations are defined by the relationships in Table 15
below.
Table 15 USB Mode Actual Sample Rates
SAMPLING
TARGET
SAMPLING
RATE
8k not exact, actual = 8.021kHz
44.1k not exact, actual = 44.118kHz
88.1k not exact, actual = 88.235kHz
All other combinations of BOSR and SR[3:0] that are not in the truth table are invalid
KHz
(Note 2)
(Note 1)
(Note 3)
44.1
88.2
32
48
96
RATE
DAC
8
KHz
44.1
88.2
48
32
96
8
8
FREQUENCY
12MHz/(250 x 48/32)
12MHz/(250 x 48/8)
not available
not available
12.000
12.000
12.000
12.000
12.000
12.000
12.000
BOSR=0
( 250FS)
MCLK
12MHz/250
12MHz/125
MHz
KHz
32
48
96
ACTUAL SAMPLING RATE
8
BOSR
0
1
0
1
0
0
1
12MHz/(272 x 11/2)
SR3
not available
not available
not available
REGISTER SETTINGS
0
1
0
1
0
0
1
BOSR=1
12MHz/272
12MHz/136
(272FS)
44.117
88.235
8.021
KHz
SAMPLE
RATE
SR2
0
0
0
0
1
1
1
SR1
0
0
0
0
1
1
1
PP Rev 1.2 November 2000
SR0
0
0
1
1
0
1
1
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DIGITAL
FILTER
TYPE
0
1
0
1
0
3
2
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