audio interface and converters

[Dimitree]

hello everyone
I have a ubs audio interface with SPDIF in and out..
obviously I can setup the interface to do this: guitar --> converter --> spdif out, and spdif in --> amp
my question is, when toying with DSP, or dsPIC or simple logic circuits, can I skip the ADC and DAC section and instead routing the spdif in/out directly to the microcontroller?