beautypg.com

Wd overflow mode register – Rainbow Electronics AT75C220 User Manual

Page 141

background image

AT75C220

141

WD Overflow Mode Register

Name:

WD_OMR

Access:

Read/write

Reset Value:0

WDEN: Watchdog Enable

0 = Watchdog is disabled and does not generate any signals.

1 = Watchdog is enabled and generates enabled signals.

RSTEN: Reset Enable

0 = Generation of an internal reset by the watchdog is disabled.

1 = When overflow occurs, the watchdog generates an internal reset.

IRQEN: Interrupt Enable

0 = Generation of an interrupt by the watchdog is disabled.

1 = When overflow occurs, the watchdog generates an interrupt.

EXTEN: External Signal Enable

0 = Generation of a pulse on the pin NWDOVF by the watchdog is disabled.

1 = When an overflow occurs, a pulse on the pin NWDOVF is generated.

OKEY: Overflow Access Key

Used only when writing WD_OMR. OKEY is read as 0.

0x234 = Write access in WD_OMR is allowed.

Other value = Write access in WD_OMR is prohibited.

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

OKEY

7

6

5

4

3

2

1

0

OKEY

EXTEN

IRQEN

RSTEN

WDEN