I made small board with Generic FIFO + CPLD to generate I2S signal.
(On the Right) DAC, and I2S to SPDIF transmitter.
(small green) FT245R board, SparcFun.com
Loopback Test, 1kHz wave - simple WAV player (source attached) - FT245R - this board - CS4394 DAC - Rolland UA1EX.
I used PC and FT245R to supply PCM data into this board, but it's not limited for PC. any MCU which has 8 bit parallel port can supply PCM data into this board.