As a development of DXO4 crossover idea.

Software will be based on Graphic Filter Designer or whatever platform will come in future.

DSP motherboard structure:



Various options for boards: (color represents standartized pinout and placement of modules on the motherboard)



The boards could be reused for standalone DAC and ADC projects by chaining them together in following ways:

DAC scenarios:



ADC scenario:



8ch I2S input module could be used with Envy24 soundcards by tripping their I2S bus.


Clocking schemes which should be considered on design stage, prior to splitting the clocking duties over blocks:

Both local, external, and ASRC-mixed implementations should be available, with sync/async receivers and ADC.

I2S (LJ with one BCLK delay = classic I2S) 16/24bit data path with 256fs masterclock were chosen by looking at the following datasheets:
PCM4220
WM8804
PCM2706/7
PCM1798
PCM1794
TDA1387T
TDA1543
WM8740

All of them accept I2S format with 256fs mclk. No issues here with Envy24-based cards, as they are at 256fs MCLK and I2S too.

AD1955 was discarded, as it requires SPI configurator to work.