LPC1347 - IRC as WatchDog Clock

[lpcware]

Content originally posted in LPCWare by BPC on Fri Feb 08 11:38:19 MST 2013
Are there any WatchDog examples for the LPC1347 which uses the IRC as the WatchDog clock?  I tried to implement it, but the device resets immediately.  This is what I tried.

- Enabled WDT config clock (SYSAHBCLKCTRL)
- Made sure the IRC was powered up (PDRUNCFG)
- Selected IRC as source (CLKSEL)
- Loaded timer value (TC)
- Enabled interrupt and armed to generate reset (MOD)
- Fed the watchdog with 0xAA then 0x55 (FEED)

Thanks.

[lpcware]

Content originally posted in LPCWare by BPC on Fri Feb 08 19:36:17 MST 2013
Thanks EC. This must be what was happening. I have the WD oscillator implemented now. The accuracy is pretty poor according to the datasheet, but works good enough for ISP purposes.

[lpcware]

Content originally posted in LPCWare by ECamino on Fri Feb 08 13:47:03 MST 2013
I did the math on RC osillator max time wwdt...was like 5.2 seconds.
Use the wdt_oscillator, and you can prescale it and select a low frequency to give you minutes of time out.

EC