Re: [avr-gcc-list] ATmega 128 Watchdog Anybody?

[Peter Bosscha]

Yeah, 

Looks to me as if Atmel decided to change the watchdog a little, the
divisor register also only loads on one of those timed accesses.
I wrote my own "mega128_wdt.h" a while ago and that seems to have fixed
it:

#define wdt_enable(timeout)                             \
        __asm__ __volatile__ (                          \
                "in __tmp_reg__, __SREG__" "\n\t"       \
                "cli" "\n\t"                            \
                "wdr" "\n\t"                            \
                "out %1, %0" "\n\t"                     \
                "out %1, %0" "\n\t"                     \
                "out __SREG__, __tmp_reg__" "\n\t"      \
                : /* no outputs */                      \
                : "r" ((uint8_t)((timeout) | BV(WDE) |
BV(WDCE))),     \
                  "I" (WDTCR)                           \
                : "r0"                                  \
        )

#define wdt_disable()                                   \
        __asm__ __volatile__ (                          \
                "in __tmp_reg__, __SREG__" "\n\t"       \
                "cli" "\n\t"                            \
                "wdr" "\n\t"                            \
                "out %1, %0" "\n\t"                     \
                "out %1, __zero_reg__" "\n\t"           \
                "out __SREG__, __tmp_reg__"             \
                : /* no outputs */                      \
                : "r" (BV(WDCE) | BV(WDE)),             \
                  "I" (WDTCR)                           \
                : "r0"                                  \
        )

Regards
Peter Bosscha


>>> address@hidden 06/03/02 09:01PM >>>
Did anybody tried the watchdog on the ATmega 128 with
Marc's GCC patch?

wdt.h doesn't subtract __SFR_OFFSET, but that was easily fixed.

But when I do

wdt_reset();
wdt_enable(7);

the watchdog resets the CPU in less than 200 ms, but it 
should happen in about 2 seconds.



Harald Kipp

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