I rent out 50% of my home. I deducted expense in Sch. E but Sch. A for Mort. Interest asks for the total amount not 50%. Is this calc'd by TTax or do i manual input?

To be safe, I recommend that you figure out manually what amount to put on Schedule A and what amount to put on Schedule E.  Turbotax may be able to do so in theory, but this is something that is easy to do incorrectly.  In other words, figure out half the mortgage interest and put in Schedule A.