Lpc2000

I'm using External Interrupt 0 to work in the falling edge. So I've 
done the following:

VPBDIV = 0;       //as described in the errata sheet
PINSEL1 |= 1;     //P0.16 as EINT0
EXTMODE = 1;     //EINT0 edge triggered
EXTPOLAR = 0;    //falling edge
EXTINT = 1;      //clearing interrupt Flag

but I'm reading 0 in EXTMODE

I've written 3 instead, and it worked fine. I'm doing something 
wrong?