A question on Addressing of peripherals in Qsys

Hi,

Background: I have generated a Qsys system. There is a 8 bit Pio in the design. After completion of the design, I assigned system address automatically.

The situation is: system is assigning an address space from x11020 to x1102f to this PIO, which makes 16 different addresses.

And the question is: Why for a single 8 bit PIO, the system is assigning 16 addresses? why? Isn't that a wastage of resources? or something there which I am missing?

Thanks in advance.

Cheers
Tahir