NEC uPD78056Y User Manual

Page 251

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251

CHAPTER 11 WATCHDOG TIMER

Figure 11-2. Timer Clock Select Register 2 Format

Caution

When rewriting TCL2 to other data, stop the timer operation beforehand.

Remarks 1. f

XX

: Main system clock frequency (f

X

or f

X

/2)

2. f

X

: Main system clock oscillation frequency

3. f

XT

: Subsystem clock oscillation frequency

4.

×

: Don't care

5. MCS : Bit 0 of oscillation mode selection register (OSMS)

6. Figures in parentheses apply to operation with f

X

= 5.0 MHz or f

XT

= 32.768 kHz.

TCL27

7

TCL26

6

TCL25 TCL24

4

0

3

2

1

0

FF42H

Address

TCL2

Symbol

TCL22 TCL21 TCL20

5

00H

After

Reset

R/W

R/W

0

0

0

0

1

1

1

1

0

0

1

1

0

0

1

1

0

1

0

1

0

1

0

1

TCL22 TCL21 TCL20

f

XX

/2

3

f

XX

/2

4

f

XX

/2

5

f

XX

/2

6

f

XX

/2

7

f

XX

/2

8

f

XX

/2

9

f

XX

/2

11

MCS = 1

f

X

/2

3

f

X

/2

4

f

X

/2

5

f

X

/2

6

f

X

/2

7

f

X

/2

8

f

X

/2

9

f

X

/2

11

MCS = 0

f

X

/2

4

f

X

/2

5

f

X

/2

6

f

X

/2

7

f

X

/2

8

f

X

/2

9

f

X

/2

10

f

X

/2

12

Watchdog Timer Count Clock Selection

0

1

TCL24

f

XX

/2

7

f

XT

(32.768 kHz)

MCS = 1

f

X

/2

7

(39.1 kHz)

MCS = 0

f

X

/2

8

(19.5 kHz)

Watchdog Timer Count Clock Selection

0

1

1

1

1

Ч

0

0

1

1

Ч

0

1

0

1

TCL27 TCL26 TCL25

Buzzer output disable

f

XX

/2

9

f

XX

/2

10

f

XX

/2

11

Setting prohibited

MCS = 1

f

X

/2

9

(9.8 kHz)

f

X

/2

10

(4.9 kHz)

f

X

/2

11

(2.4 kHz)

MCS = 0

f

X

/2

10

(4.9 kHz)

f

X

/2

11

(2.4 kHz)

f

X

/2

12

(1.2 kHz)

Buzzer Output Frequency Selection

(625 kHz)

(313 kHz)

(156 kHz)

(78.1 kHz)

(39.1 kHz)

(19.5 kHz)

(9.8 kHz)

(2.4 kHz)

(313 kHz)

(156 kHz)

(78.1 kHz)

(39.1 kHz)

(19.5 kHz)

(9.8 kHz)

(4.9 kHz)

(1.2 kHz)

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