Section 11 Watchdog Timer (WDT)
Rev. 3.00 Sep. 27, 2007 Page 409 of 758
REJ09B0243-0300
WTCNT value
H'FF
H'00
WDTOVF
signal
Internal reset signal
(power-on reset selected)
Overflow occurs
H'00 is written
to WTCNT
WT/IT = 1
TME = 1
H'00 is written
to WTCNT
Count starts
WOVF = 1
WDTOVF
is asserted and
an internal reset is generated
32 P
φ
clock
Internal reset signal
(manual reset selected)
18 P
φ
clock
Time
3 P
φ
+ one cycle of count clock
Figure 11.3 Operation in Watchdog Timer Mode
(When WTCNT Count Clock is Specified to P
φ
/32 by CKS2 to CKS0)
11.4.3
Using Interval Timer Mode
When operating in interval timer mode, interval timer interrupts are generated at every overflow of
the counter. This enables interrupts to be generated at set periods.
1. Clear the WT/IT bit in WTCSR to 0, set the type of count clock in the CKS2 to CKS0 bits, and
set the initial value of the counter in the WTCNT counter.
2. Set the TME bit in WTCSR to 1 to start the count in interval timer mode.
3. When the counter overflows, the WDT sets the IOVF flag in WTCSR to 1 and an interval
timer interrupt request is sent to the INTC. The counter then resumes counting.
Summary of Contents for SH7124 R5F7124
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Page 36: ...Section 1 Overview Rev 3 00 Sep 27 2007 Page 16 of 758 REJ09B0243 0300 ...
Page 68: ...Section 2 CPU Rev 3 00 Sep 27 2007 Page 48 of 758 REJ09B0243 0300 ...
Page 108: ...Section 5 Exception Handling Rev 3 00 Sep 27 2007 Page 88 of 758 REJ09B0243 0300 ...
Page 166: ...Section 7 User Break Controller UBC Rev 3 00 Sep 27 2007 Page 146 of 758 REJ09B0243 0300 ...
Page 724: ...Section 20 List of Registers Rev 3 00 Sep 27 2007 Page 704 of 758 REJ09B0243 0300 ...
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