Datasheet

Section 14 Watchdog Timer (WDT)
Rev.7.00 Mar. 18, 2009 page 681 of 1136
REJ09B0109-0700
14.3.3 Reset Control/Status Register (RSTCSR)
RSTCSR controls the generation of the internal reset signal when TCNT overflows, and selects
the type of internal reset signal. RSTCSR is initialized to H'1F by a reset signal from the RES pin,
but not by the WDT internal reset signal caused by overflows.
Bit Bit Name Initial Value R/W Description
7 WOVF 0 R/(W)
*
Watchdog Timer Overflow Flag
This bit is set when TCNT overflows in watchdog
timer mode. This bit cannot be set in interval timer
mode, and only 0 can be written.
[Setting condition]
Set when TCNT overflows (changed from H'FF to
H'00) in watchdog timer mode
[Clearing condition]
Cleared by reading RSTCSR when WOVF = 1, and
then writing 0 to WOVF
6 RSTE 0 R/W Reset Enable
Specifies whether or not a reset signal is generated
in the chip if TCNT overflows during watchdog
timer operation.
0: Reset signal is not generated even if TCNT
overflows
(Though this LSI is not reset, TCNT and TCSR in
WDT are reset)
1: Reset signal is generated if TCNT overflows
5 — 0 R/W Reserved
Can be read and written, but does not affect
operation.
4
to
0
— All 1 — Reserved
These bits are always read as 1 and cannot be
modified.
Note: * Only a write of 0 is permitted, to clear the flag.