User manual

DE2 User Manual
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4.8 Using the 24-bit Audio CODEC
The DE2 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 4.15, and the FPGA pin assignments are listed in Table 4.9. Detailed information
for using the WM8731 codec is available in its datasheet, which can be found on the manufacturer's
web site, and from the Datasheet folder on the DE2 System CD-ROM.
Figure 4.15. Audio CODEC schematic.
Signal Name FPGA Pin No. Description
AUD_ADCLRCK PIN_C5 Audio CODEC ADC LR Clock
AUD_ADCDAT PIN_B5 Audio CODEC ADC Data
AUD_DACLRCK PIN_C6 Audio CODEC DAC LR Clock
AUD_DACDAT PIN_A4 Audio CODEC DAC Data
AUD_XCK PIN_A5 Audio CODEC Chip Clock
AUD_BCLK PIN_B4 Audio CODEC Bit-Stream Clock
I2C_SCLK PIN_A6 I2C Data
I2C_SDAT PIN_B6 I2C Clock
Table 4.9. Audio CODEC pin assignments.