We are developing a product, where the sleep current is critical.
How can we minimize the leakage current for the unused pins of the controller?
(As far as I know, a CMOS input can consume some uA, when floating, because of the internal CMOS structures. It will float somewhere "mid supply", and both pull up and pull-down transistors will conduct a little bit. An input with pull up or pull down should be theoretically better, than a complete floating input. However there is an input enable bit, so the input can be disabled, but I'm not sure about the effect, especially leakage current-wise.)
Disabling the input through the input enable bit will help in minimizing the current consumption.