nds card pin activation

hi everyone i am doing a haking project on my ds with rfid modules , i comunicate withe spi interface between the nintendo and the rfid module but i need one extra pin to activate the module, resuming i have
clk,mosi,miso,cs, for spi but i want to be able to controle another output pin, can anyone tell me how do i do this in c code, i am ussing devkitpro withe palib
on a visual c++ enviorment. sorry for may inglish.

hi will try to take pictures of my project for you all to see.thanks