Sometimes setting some of the I/O pins as outputs at the proper level can be better for lowest overall power. You need to study what each specific attached device does to each 'LPC932 pin while that device is powered down.

I once did a very similar design and was able to reduce current to less than 2 uA but to get there required careful evalation and real world testing of every pin. That design used a scheme wherein the keypad was coupled to the processor RESET in a way to introduce a hardware reset to the processor when a key was pressed. (That processor did not have the keypad interrupt feature that the 'LPC932 has).

Michael Karas