r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 845

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

14.3
The WDT has the following three registers. To prevent accidental overwriting, TCSR, TCNT, and
RSTCSR have to be written to in a method different from normal registers. For details, refer to
section 14.6.1, Notes on Register Access.
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•
•
14.3.1
TCNT is an 8-bit readable/writable up-counter. TCNT is initialized to H'00 when the TME bit in
TCSR is cleared to 0.
14.3.2
TCSR selects the clock source to be input to TCNT, and the timer mode.
Bit
7
Timer counter (TCNT)
Timer control/status register (TCSR)
Reset control/status register (RSTCSR)
Bit Name
OVF
Register Descriptions
Timer Counter (TCNT)
Timer Control/Status Register (TCSR)
Initial Value
0
R/W
R/(W) *
Description
Overflow Flag
Indicates that TCNT has overflowed in interval
timer mode. Only a write of 0 is permitted, to clear
the flag.
[Setting condition]
When TCNT overflows in interval timer mode
(changes from H'FF to H
When internal reset request generation is selected
in watchdog timer mode, OVF is cleared
automatically by the internal reset.
[Clearing conditions]
Cleared by reading TCSR when OVF = 1, then
writing 0 to OVF
Rev. 1.00 Sep. 19, 2008 Page 815 of 1342
Section 14 Watchdog Timer (WDT)
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00)
REJ09B0467-0100