my sd card for my nintendo dsi console doesnt work?

hi can anyone help me? i have a nintendo dsi console ive brought a sd card and a sd adapter for it and when i put them in the console a message comes up the card in the sd card slot entered says can not be used does anyone know what the problem is? thanks also i brought a r4 card and when i put that in the back of console and switch it on nothing comes up in the menu does any one know what the problem is there? thank you

joshnshaz
October 2011