Wake up from deep sleep

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by mhjerde on Tue Dec 11 07:01:43 MST 2012
I have this weird behavior where I can put the mcu in sleep and wake it up with an interrupt on P2.10. But if I put it in deep sleep, it won't wake up.
The MCU is an LPC1756.

The only code change is adding the line

SCB->SCR = 0x4;

So this works:
LPC_SC->PCON = 0x00;

But it wont wake up after this:
SCB->SCR = 0x4;
LPC_SC->PCON = 0x00;

The code immediately following __WFI() restarts the MCU:

WDT_Init(WDT_CLKSRC_IRC, WDT_MODE_RESET);// Initialize WDT, IRC OSC, interrupt mode
WDT_Start(500000);// restart time in us (sec/1000000)
while(1); //infinite loop to wait chip reset from WDT

Any suggestions? If I assume the interrupt fires, so maybe the error is in the WDC restart code?