irda on de2 problems?

hello everyone!

recently i am working with the de2 board, now i find there are no examples about the irda on the board. then i download the irda ip core from the university program IP cores. But when i use it in niosII,by calling the alt_up_irda_read_data function, it always returns constant value "255" no matter which key is pressed.

so what's the problem? did anyone have the same problem before?please give me some advice, thank you very much!!