I think somehow my problems are connected with me not talking them out enough in my head. I struggled with this problem all day yesterday and dreamed about it all night. I tried everything I could think of and then sent you that email. Now, less than an hour later, I have it working!
First, I’ve realized that I was never setting the volume correctly in my Slave host, because the level is 2’s compliment, so writing all 0xFF attenuates the signal all the way, where I thought it would be turning it up all the way. Secondly, the only reason I thought it ever worked was because I think when you program the device in Autonomous mode, it sets the volumes correctly, and then when you re-program in host mode, it leaves the volumes alone until the host changes them. This was throwing me off, because at times it was working, but I think it was only because I had just re-programmed the device between autonomous and then host, without trying to write to the volume register.
I may be still confused somewhat on this, but I am able to now consistently set both the input and output local slave volume through the host and both channels are working.
Thanks,