I have a very peculiar problem going on in a design of mine with a BF527 and the internal SSM2602. I'm using both the mic and line in inputs and when I select the mic input, I do get - as expected - the mic going to the AD but when I select the line in (register 4 bit 2), I get BOTH the line and mic. Note that I have both sidetone and line bypass off. Further more, when I select line in, I turn on the Mic Mute before the "Mux" and I STILL GET the Mic as well as the line.
I'm sort of at a loss here. Has anyone seen anything like this? How is this even possible when the datasheet Clearly states that it's an exclusive multiplexer. I'm pretty sure there is no crosstalk problems on our layout (if anything, the line would feed into the mic input not the other way around).
I am not sure if you are still working on this.
As you said when line is selected even mic mute is not working, but does the mic mute and other functions work properly when mic is selected?
Have you observed the same behaviour on multiple devices or only on this particular board?