![Rabbit 3000 Скачать руководство пользователя страница 95](http://html2.mh-extra.com/html/rabbit/3000/3000_user-manual_3114034095.webp)
User’s Manual
87
The code to do this may also hit the watchdog with a 0.25-second period to speed up the
reset. Such watchdog code must be written so that it is highly unlikely that a crash will
incorporate the code and continue to hit the watchdog in an endless loop. The following
suggestions will help.
1. Place a jump to self before the entry point of the watchdog hitting routines. This pre-
vents entry other than by a direct call or jump to the routine.
2. Before calling the routine, set a data byte to a special value and then check it in the rou-
tine to make sure the call came from the right caller. If not, go into an endless loop with
interrupts disabled.
3. Maintain data corruption flags and/or checksums. If these go wrong, go into an endless
loop with interrupts off.
Table 7-8. Watchdog Timer Test Register (WDTTR adr = 09h)
Bit(s)
Value
Description
7:0
51h
Clock the least significant byte of the WDT timer from the peripheral
clock. (Intended for chip test and code 54h below only.)
52h
Clock the most significant byte of the WDT timer from the peripheral
clock. (Intended for chip test and code 54h below only.)
53h
Clock both bytes of the WDT timer, in parallel, from the peripheral clock.
(Intended for chip test and code 54h below only.)
54h
Disable the WDT timer. This value, by itself, does not disable the WDT
timer. Only a sequence of two writes, where the first write is 51h, 52h or
53h, followed by a write of 54h, actually disables the WDT timer. The
WDT timer will be re-enabled by any other write to this register.
other
Normal clocking (32 kHz oscillator) for the WDT timer. This is the
condition after reset.
Содержание 3000
Страница 1: ...Rabbit 3000 Microprocessor User s Manual 019 0108 020426 A...
Страница 8: ...Rabbit 3000 Microprocessor...
Страница 28: ...20 Rabbit 3000 Microprocessor...
Страница 73: ...User s Manual 65 6 RABBIT INTERNAL I O REGISTERS...
Страница 122: ...114 Rabbit 3000 Microprocessor...
Страница 138: ...130 Rabbit 3000 Microprocessor...
Страница 150: ...142 Rabbit 3000 Microprocessor...
Страница 188: ...180 Rabbit 3000 Microprocessor...
Страница 208: ...200 Rabbit 3000 Microprocessor...
Страница 228: ...220 Rabbit 3000 Microprocessor...
Страница 232: ...224 Rabbit 3000 Microprocessor...
Страница 238: ...230 Rabbit 3000 Microprocessor...
Страница 260: ...252 Rabbit 3000 Microprocessor...
Страница 266: ......