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2 wtbr: sub-second registers – FUJITSU MB91460 SERIES FR60 User Manual

Page 970

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954

Chapter 49 Real-Time Clock

4.Registers

4.2 WTBR: Sub-Second Registers

These registers are used to hold values to be reloaded to the 21 bit down counter.

• WTBR0: Address 04A5

H

(Access: Byte, Half-word, Word)

• WTBR1: Address 04A6

H

(Access: Byte, Half-word, Word)

• WTBR2: Address 04A7

H

(Access: Byte, Half-word, Word)

(For attributes, refer to “

Meaning of Bit Attribute Symbols (Page No.10)

”.)

The sub-second registers, WTBR, holds values to be reloaded to the 21 bit down counter. When the 21 bit
down counter value becomes “0”, the settings of WTBR are reloaded to the 21 bit down counter.

(See

8. Caution (Page No.961)

”.)

Remark: The reload value to be set in the sub-second registers corresponds to the time for half a second. One
second is reached after counting twice the reload value set in WTBR.

(See

7.1 How do I set the count period of 1 second? (Page No.959)

”.)

WTBR0

7

6

5

4

3

2

1

0

bit

D20

D19

D18

D17

D16

X

X

X

X

X

Initial value

Unchanged Unchanged Unchanged Unchanged Unchanged

When reset

RX/WX

RX/WX

RX/WX

R/W

R/W

R/W

R/W

R/W

Attribute

WTBR1

7

6

5

4

3

2

1

0

bit

D15

D14

D13

D12

D11

D10

D9

D8

X

X

X

X

X

X

X

X

Initial value

Unchanged Unchanged Unchanged Unchanged Unchanged Unchanged Unchanged Unchanged

When reset

R/W

R/W

R/W

R/W

R/W

R/W

R/W

R/W

Attribute

WTBR2

7

6

5

4

3

2

1

0

bit

D7

D6

D5

D4

D3

D2

D1

D0

X

X

X

X

X

X

X

X

Initial value

Unchanged Unchanged Unchanged Unchanged Unchanged Unchanged Unchanged Unchanged

When reset

R/W

R/W

R/W

R/W

R/W

R/W

R/W

R/W

Attribute