Audio Codec(ADPCM 1-Bit)
The code is ready for Altera Cyclone-II DE1 Starter board and it is tested, you can modify codes and use them in any project.
Sampling Frequency: 44100Hz
Bit-rate: 1 Bit Per Sample(So it is: 44.1 * 2 = 88.2kbps)
Compression Ratio: 16:1
VHDL code consists:
1-bit ADPCM Decoder(x2), I2S Driver(x1), I2C Driver(x1), Flash Memory Driver(x1), Keyboard Driver(x1), LED Bar(x1), Volume and Config Engine(x1).
Codec(Encoder/Decoder) is available in Win32 application that you can use it to encode PCM RAW wave files, then burn the *.DJ file into the flash, make sure the flash is already clear(you can use the EDK control panel to clear and program the flash) and run the code on FPGA.
There is no patent or copyright, it's free for everyone to use in any project.
(if you need the Encoder in VHDL, contact me by e-mail.)