WDT clarifications

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by Genesy on Wed Oct 16 03:45:22 MST 2013
I looked the old example of WDT for LPC11xx (not the new LPCOpen driver).
I read in the manual that the WDT has a frequency clock of 8Khz with a fixed prescaler of 4.
Then, if I'm not mistaken, the WDT timer step is of:
1/8000 * 4 = 0,0005 s = 500us
though the minimun counter value is of 256(0xff)
then the minimum interval is of 0,0005 * 256 = 0,128ms.
In the driver that I looked there isn't a way to set the counter value, but it is initialized by the WDTInit() function,
that haven't parameter, at the default value of 1023(0x3FF).
For this value, then the interval is of 0,0005*1023 = 0,5115 s = 511,5 ms is right?
In the driver_config.h file there is also a defined macro WDT_FEED_VALUEthat is set at (8000*1),
but it doesn't seem to used in the program.  What is this macro?

Thank you very much