How to use RIO interrupt with RCM 6760.

Question

We have RIO connect to RCM6760. I want to use interrupt method whenever RIO input is toggle. Can you point me to the right direction?

I tried the following and it is not working for me.

codes:
main()
{
WrPortI(PEDDR, &PEDDRShadow, 0x00); // set port E as all inputs
SetVectExtern(1, my_isr1);
WrPortI(I1CR, &I1CRShadow, 0x09); // enable external INT1 on PE5, rising
edge,priority 1

WrPortE(MCR_REG,NULL,0x01);//enble interuppt for IO

}