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2 input/output pins, 3 register descriptions, 1 timer counter (tcnt) – Renesas H8S/2111B User Manual

Page 257

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Rev. 1.00, 05/04, page 223 of 544

11.2 Input/Output

Pins

The WDT has the pins listed in table 11.1.

Table 11.1 Pin Configuration

Name Symbol

I/O

Function

Reset output pin

RESO

Output

Outputs the counter overflow signal in
watchdog timer mode

External sub-clock input pin EXCL

Input

Inputs the clock pulses to the WDT_1
prescaler counter

11.3 Register

Descriptions

The WDT has the following registers. To prevent accidental overwriting, TCSR and TCNT have
to be written to in a method different from normal registers. For details, refer to section 11.6.1,
Notes on Register Access. For details on the system control register, refer to section 3.2.2, System
Control Register (SYSCR).

• Timer counter (TCNT)
• Timer control/status register (TCSR)

11.3.1

Timer Counter (TCNT)

TCNT is an 8-bit readable/writable up-counter.

TCNT is initialized to H'00 when the TME bit in the timer control/status register (TCSR) is
cleared to 0.

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