I'm working on a digital aux-in project. I've been using the Eutronix digital out board for a while now and wanted to add digital in from my XM unit.

I lifted the CD2 input pins of the 7705 DSP and routed an I2S signal in from the XM unit. I then modified the hijack kernel DSP programming in empeg_mixer.c to select CD2 when aux-in is selected.

However, there seems to be some sort of issue with a mute function. When I turn on the XM unit I get an audio click and then silence. The display will increment "XM 1", "XM 2", etc... so I know it's seeing something.

I know the CS4231A can be programmed to sample the analog aux in and display bar graphs, etc. If no analog signal is seen, will it automatically mute? If so, where is this code?

Thanks for the help...
-Jon