Operation - Fujitsu MB91460 SERIES FR60 User Manual

Chapter 20 Software Watchdog Timer

5.Operation

5. Operation
This section describes the watchdog operation.
5.1 Watchdog (Detecting Runaway)
Count value of
the timer counter
(1)
Interval period
selection
Bit output of
the timer counter
(Bits 15, 17, 19 and 21)
Watchdog timer
Reading from the RSRR
register
Periodically writing
"A5" and "5A" in the
WPR register
WDOG bit
Setting initialization reset
(INIT)
(1) Setting interval time
(2) Watchdog startup (Watchdog timer clear)
(3) Interval signal output from the timebase counter. The watchdog timer counts.
(4) Within the interval time, by software periodic writing to the WPR register with "A5" and "5A" has been performed.
The watchdog timer clears.
(5) Within the interval time, by software periodic writing to the WPR register with "A5" and "5A" has been performed.
The watchdog timer clears.
(6) Interval signal output from the timebase counter. The watchdog timer counts.
(7) Within the interval time, by software periodic writing to the WPR register with "A5" and "5A" has been performed.
Watchdog timer clears.
(8) Interval signal output from the timebase counter. The watchdog timer counts.
(9) MCU runs away (the runaway of MCU is assumed).
(10) Within interval time, by software writing to the WPR register with "A5" and "5A" has not been performed.
(11) Interval signal output from the timebase counter. The watchdog timer counts.
(12) Runaway is detected, WODOG flag has been changed to "1".
(13) Watchdog reset (INIT) has been generated.
278
(3)
(3)
Watchdog
(3) (4)
startup
(2)
(4)
Clear by
software
Normal operation
(8)
(6)
(8)
(6)
(7)
(5) (6) (8)
(5) (7)
Clear by
Clear by
software
software
(11)
(12)
Runaway
detection
(10)
With
no clear
(12)
(13)
Runaway Reset
(9)