Can't get WWDT on LPC4357 to start

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by dsw on Thu Dec 26 15:33:54 MST 2013
I’m having trouble getting the watchdog timer to start on the LPC4357.
I use the code:

void Main_Watchdog_Init(void)

   LPC_WWDT->TC = 0xffff;           //relatively small value for timeout.
   LPC_WWDT->MOD =                 //See page 964 of LPC4357 spec
                                       (1 << 1)    //Watchdog timeout will cause a chip reset.
                                     +(1 << 4);
   LPC_WWDT->MOD =                //See page 964 of LPC4357 spec
                                      (1 << 0);  //Enable watchdog timer.
   Main_Watchdog_Feed();            //Feeding the watchdog once should start it.

   LPC_WWDT->FEED = 0x01;        //This should cause immediate reset.
   LPC_WWDT->FEED = 0x02;
   LPC_WWDT->FEED = 0x03;

static __INLINE void Main_Watchdog_Feed(void)
     LPC_WWDT->FEED = 0xAA;
     LPC_WWDT->FEED = 0x55;

but the watchdog timer never starts decrementing, LPC_WWDT->TV never changes from its reset value of 0x000000FF.
Even though I never feed the watchdog again, I never get a reset.
Thru the debugger I can verify that LPC_WWDT->MOD = 0x00000013, which should be the correct value to enable it to run.
Can anyone think of something I’m missing?