EM78611

Universal Serial Bus Microcontroller Series

Preliminary

10

06/10/2003 (V1.0)

R3 (Status Register)

Default Value:(0B_0001_1XXX)

7

6

5

4

3

2

1

0

PS2

PS1

PS0

T

P

Z

DC

C

R3 [0]

Carry flag.

R3 [1]

Auxiliary carry flag.

R3 [2]

Zero flag. It will be set to 1 when the result of an arithmetic or logic operation is

zero.

R3 [3]

Power down flag. It will be set to 1 during Power-on phase or by “WDTC” command

and cleared when the MCU enters into Power down mode. It remains in previous

state after WatchDog Reset.

1: Power-on.

0: Power down

R3 [4]

Time-out flag. It will be set to 1 during Power-on phase or by “WDTC” command. It

is reset to 0 by WDT time-out.

1: WatchDog timer no overflow.

0: WatchDog timer overflow.

The various states of Power down flag and Time-out flag at different conditions are shown

below:

T

P

Condition

1

1

0

1

1

1

1

*P

0

0

Power-on reset

WDTC instruction

WDT time-out

Power down mode

Wakeup caused by port change during Power down mode

*P: Previous status before WDT reset

R3 [5-7] Page selection bits. These three bits are the used to select the page of program

memory.

PS2

PS1

PS0

Program Memory Page [Address]

0

0

0

Page 0 [0000-03FF]

0

0

1

Page 1 [0400-07FF]

0

1

0

Page 2 [0800-0BFF]

0

1

1

Page 3 [0C00-0FFF]

1

0

0

Page 4 [1000-13FF]

1

0

1

Page 5 [1400-17FF]