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DE2-70 User Manual
48
5.8 Using the 24-bit Audio CODEC
The DE2-70 board provides high-quality 24-bit audio via the Wolfson WM8731 audio CODEC
(enCOder/DECoder). This chip supports microphone-in, line-in, and line-out ports, with a sample
rate adjustable from 8 kHz to 96 kHz. The WM8731 is controlled by a serial I2C bus interface,
which is connected to pins on the Cyclone II FPGA. A schematic diagram of the audio circuitry is
shown in Figure 5.14, and the FPGA pin assignments are listed in Table 5.12. Detailed information
for using the WM8731 codec is available in its datasheet, which can be found on the manufacturer's
web site, or in the Datasheet/Audio CODEC folder on the DE2-70 System CD-ROM.
I2C_SDAT
AUD_BCLK
AUD_DACLRCK
AUD_ADCLRCK
AUD_DACDAT
I2C_SCLK
AUD_XCK
AUD_ADCDAT
AGND
AGND
AGND
AGND
AG
ND
AGND
AGND
AGND
AGND
AGND
AGND
AGND
AGND
A_VCC33
A_VCC33
A_VCC33
VCC33
VCC33
I2C ADDRESS READ IS 0x34
I2C ADDRESS WRITE IS 0x35
LINE IN
MIC I
N
LINE OUT
R104
680
R104
680
C38
1u
C38
1u
C39
1u
C39
1u
R103
330
R103
330
R106
47K
R106
47K
C42
1n
C42
1n
C44
100u
C44
100u
J10
PHONE JACK P
J10
PHONE JACK P
L
1
R
2
GND
3
NCR
4
NCL
5
C40
1u
C40
1u
J11
PHONE JACK B
J11
PHONE JACK B
L
1
R
2
GND
3
NCR
4
NCL
5
R107
47K
R107
47K
C43
100u
C43
100u
R105
47K
R105
47K
R102
4.7K
R102
4.7K
R108
2K
R108
2K
R101
4.7K
R101
4.7K
R109
2K
R109
2K
U13
WM8731
U13
WM8731
BCLK
7
HPVDD
12
XTO
2
DCVDD
3
MBIAS
21
MICIN
22
RLINEIN
23
LLINEIN
24
MODE
25
CSB
26
SDIN
27
SCLK
28
ROUT
17
AVDD
18
AGND
19
VMID
20
LOUT
16
HPGND
15
RHPOUT
14
LHPOUT
13
XTI/MCLK
1
DGND
4
ADCLRCK
11
ADCDAT
10
DBVDD
5
CLKOUT
6
DACDAT
8
DACLRCK
9
EXPOSED
29
R100
4.7K
R100
4.7K
J12
PHONE J
ACK G
J12
PHONE J
ACK G
L
1
R
2
GND
3
NCR
4
NCL
5
C41
10u
C41
10u
R99
4.7K
R99
4.7K
Figure 5.14. Audio CODEC schematic.
Signal Name FPGA Pin No. Description
AUD_ADCLRCK PIN_F19 Audio CODEC ADC LR Clock
AUD_ADCDAT PIN_E19 Audio CODEC ADC Data
AUD_DACLRCK PIN_G18 Audio CODEC DAC LR Clock
AUD_DACDAT PIN_F18 Audio CODEC DAC Data
AUD_XCK PIN_D17 Audio CODEC Chip Clock
AUD_BCLK PIN_E17 Audio CODEC Bit-Stream Clock
I2C_SCLK PIN_J18 I2C Data
I2C_SDAT PIN_H18 I2C Clock
Table 5.12. Audio CODEC pin assignments.