Am 15.03.2011 12:12, schrieb JMGross: > > ----- Ursprüngliche Nachricht ----- > Von: Crazy Casta > Gesendet am: 14 Mrz 2011 17:24:55 > >> I would like to concur with the suggestion that we leave the wdt alone >> (except for pinging) by default. All the ti datasheets talk about the need >> to disable the watchdog. It would seem to be more confusing to operate >> differently wrt the to docs (harder for those of us who have read and are >> familiar with the to docs). > > It's not only that the datasheets talk about disabling the watchdog. > Disabling an already disabled watchdog does no harm.
neither is enabling it again a problem, if you actively want to use it. in that case you only have a small time during startup where the protection is not good. however the startup phase is a few milliseconds compared to hours or months of normal operation afterwards. a hardware watchdog is also often used to protect against programming errors (e.g. not enough stack space for all combinations of interrupts and foreground code). this kind of protection is not needed during startup as the code there is proven (and interrupts locked). it is an issue when you expect extreme EMI, during startup, that disturbs the operation of the CPU, causing it run faulty instructions. however, in such a scenario, what makes you think that the WDT module continues to work properly... (i've never seen an MSP running faulty by EMI. i've only see it behaving badly when the clock was out of specs. that's one of the points that the F2xx fixed, compared to F1xx. there is an additional glitch filter for MCLK) > It is that the watchdog is specified to be enabled after a reset, > so if you rely on this info, you're hosed if it got disabled in the startup. > IMHO the main reason for a watchdog is that it is active and working > unless you explicitely don't want it. Else you don't need a watchdog > at all. if you want to rely on the watchdog, you should also realize that you have to reset the WDT module - in your application - before it expires and resets. i'd also point out that using a WDT module correctly requires some thinking. just restarting it all over your code isn't giving good protection. restarting it in interrupt handlers isn't good either (as interrupts may still somehow work even when SP points to non-RAM). chris ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ Mspgcc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mspgcc-users
