Sigma DE2-70 manual Audio Recording and Playing, Nios II IDE

DE2-70 User Manual

6.10 Audio Recording and Playing

This demonstration shows how to implement an audio recorder and player using the DE2-70 board with the built-in Audio CODEC chip. This demonstration is developed based on SOPC Builder and

NIOS II IDE.

Figure 6.18 shows the man-machine interface of this demonstration. Two push buttons and six toggle switches are used for users to configure this audio system: SW0 is used to specify recording source to be Line-in or MIC-In. SW1 is to enable/disable MIC Boost when the recoding source is MIC-In. SW2 is used to enable/disable Zero-Cross Detection for audio playing. SW3, SW4 and SW5 are used to specify recording sample rate as 96K, 48K, 44.1K, 32K, or 8K. The 16x2 LCD is used to indicate the Recording/Playing status. The seg7 is used to display Recording/Playing duration with time unit in 1/100 second. The LED is used to indicate the audio signal strength. Table 6.4 summarizes the usage of toggle switches for configuring the audio recorder and player.

Record/Play Status

Record/Play Duration

Signal Strength

Play

Sample rate	Record
	Audio Source

MIC Boost

Zero-Cross Detect

Figure 6.18. Man-Machine Interface of Audio Recorder and Player.

Figure 6.19 shows the block diagram of the design of the Audio Recorder and Player. There are hardware part and software part in the block diagram. The software part means the Nios II program that stored in SSRAM. The software part is built by Nios II IDE in C programming language. The

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