CCU3000 Datasheet, PDF (20/77 Pages) Micronas – Central Control Unit

CCU 3000, CCU 3000-I
CCU 3001, CCU 3001-I
Sequence in the main loop:
LDA watchdog_value
CMP #WATCHDOG_TIME
BNE SKIP_WD
;
STA watchdog_address
EOR #$FF
STA watchdog_value
SKIP_WD
...
Remark:
It is important to program the watchdog register with the
new value before this value is memorized in the shadow
variable, because this procedure could be interrupted by
the interrupt, which will program the watchdog with the
complementary value.
D0...D7
SWATCH
R/W
latch
latch
==
D
Q
CLR
+
D
Q
CLR ^Q
RESET active
RES_DOG_1
Φ2
=
RES_DOG
8–bit
counter
CLR
16–bit
POWER
down
Φ2
R/W
SWATCH
EN D0
Fig. 2–17: Watchdog
Φ2
D0...D7
SWATCH
R/W
RES_DOG_1
Fig. 2–18: Timing watchdog
20
Trigger
watchdog is
retriggered
MICRONAS INTERMETALL