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faessler
Joined: 28 Nov 2003
Posts: 3
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| Variable watchdog resistent (reset resistent) |
 Posted: Mon Aug 09, 2004 2:43 am |
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Hello,
it is possible to use a variable after reset or watchdog ?
example:
int testvar;
...
if (restart_cause() == WDT_TIMEOUT)
{
testvar++;
if (testvar == 5)
printf ("Ohh we have now 5 restarts ... ");
}
...
It is possible ?
regards
Oliver |
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Guest
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| Posted: Mon Aug 09, 2004 5:08 am |
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Register file is fully static so you can use it.
Don't forget to clear your variable on power-on reset (take a look on Restart_cause() function). |
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Ttelmah
Guest
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| Re: Variable watchdog resistent (reset resistent) |
| Posted: Mon Aug 09, 2004 5:26 am |
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| faessler wrote: | Hello,
it is possible to use a variable after reset or watchdog ?
example:
int testvar;
...
if (restart_cause() == WDT_TIMEOUT)
{
testvar++;
if (testvar == 5)
printf ("Ohh we have now 5 restarts ... ");
}
...
It is possible ?
regards
Oliver |
Yes.
However you have to be careful of the 'self clear' behaviour of the compiler. If (for instance), you have 'zero_ram' set, all memory will be lost on the restart. Similarly, a variable declared as 'static', will also be cleared. Variables declared inside a routine, may well be cleared/overwritten by earlier code.
Hence the only safe variable declaration for this type of operation, is a default global (where the variable is declared outside any function), with no 'zero_ram' declaration.
Also remember to read the 'restart_cause', right near the start of the program. This ensures the flag is correctly cleared, in case something happens early in the code.
Best Wishes |
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