Remote-processing RPC-330 Manuel d'utilisateur télécharger pdf (Page 40)

WATCHDOG TIMER SECTION 11

Page 11-1 RPC-330

DESCRIPTION

The watchdog timer is used to reset the RPC-330 if the

program or CPU "crashes". The timer is built into the

80C320 CPU. Timed access requirem ents built into the

CPU make it high ly unlikely an er rant pr ocessor would

cancel a watchdog timer.

The watchdog should not be used in loops which do not

end quickly or are of indeterminate duration unless a

WDOG command is included. An example of an

indeterminate loop is one that waits for a port condition

to change.

The timer is set by executing a WDOG n command. n is

0, 1, or 2. 0 turns off the timer. 1 sets the watch dog

time to 380 ms while 2 sets it to 2.8 seconds. Executing

WDOG by itself resets the timer. WD OG must be

executed periodically to prevent a reset.

EXTERNAL RESET

The card is reset externally by momentarily shorting

W10[1-2]. Reset is also achiev ed by shor ting W10-2 to

ground. Maintain this short for at least 10 ms. The card

will then reset for about 350 ms.

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Remote-processing RPC-330 Manuel d'utilisateur Page 40