# Deep power down mode in LPC17xx

I am currently working on a home project. I want to put my LPC1769 in deep power down mode. this is the code I have so far:

SCR |= (1 << SLEEPDEEP);
PCON |= (1 << PM1);


It doesn't work, I don't know why. I read something about __WFI() and __WFE(), I tried to implement this, but the following error appeared:

__WFI was not declared in this scope

Can someone help to to put my LPC1769 in deep power down mode?

You are not including CMSIS headers (eg. cmsis_gcc.h or another, it probably has to be included via another file like core_cm3.h).
asm("wfe");