Rainbow Electronics AT89C5122 User Manual

Page 178

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178

AT8xC5122/23

4202E–SCR–06/06

Reset Value = XXXX X000b

The three lower bits (S0, S1, S2) located into WDTPRG register enables to program the
WDT duration.

To compute WD Timeout, the following formula must be applied:

Time Out = 6 * (2

14

* 2

Svalue

- 1 ) / F

CK_WD

Note:

Svalue represents the decimal value of (S2 S1 S0)

Table 109. Watchdog Timer Out Register - WDTPRG (0A7h)

7

6

5

4

3

2

1

0

-

-

-

-

-

S2

S1

S0

Bit

Number

Bit

Mnemonic

Description

7 - 3

-

Reserved
The value read from this bit is indeterminate. Do not change these bits.

2

S2

WDT Time-out select bit 2

1

S1

WDT Time-out select bit 1

0

S0

WDT Time-out select bit 0

Table 110. Machine Cycle Count

S2

S1

S0

Machine Cycle Count

0

0

0

2

14

- 1

0

0

1

2

15

- 1

0

1

0

2

16

- 1

0

1

1

2

17

- 1

1

0

0

2

18

- 1

1

0

1

2

19

- 1

1

1

0

2

20

- 1

1

1

1

2

21

- 1

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