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IWDG & WWDG for stm8l151c6 halt active mode

Question asked by ma.wenbing on Jun 13, 2013
Latest reply on Oct 27, 2013 by hoeneveld.bill
I want to use stm8L watch dog in halt/halt-active mode. my system wakes up by RTC.

1. when I choice Independent watchdog, a watchdog reset happens when system is in halt/halt-active mode. As you know, the option byte(0x4808) default setting is IWDG still runing in halt/halt active, if you do not feed watchdog, a watchdog reset happens. I do not want to feed watch dog in interrupt routine, So I choice Window watchdog.

2. WWDG stop runing in halt/halt-active mode according to option byte configuration. it is difficult to feed watch dog in allowed watchdog window. stm8l runs at 16MHz, It means WWDG must be refreshed in about 50ms. but in my task scheduler, it maybe take more than 50ms when task processing so that the refresh allowed missed. I do not want to use timer interrupt to feed watchdog. I don't have good idea to handle WWDG.

3. I choice IWDG again. after powers up, check the option byte and configure the IWDG stop runing in halt/halt-active mode. It seems works well. Is there some potential issue to modify option bytes?