at89c51cc02ua-tdsum ATMEL Corporation, at89c51cc02ua-tdsum Datasheet - Page 70

• Manufacturer Part Number: at89c51cc02ua-tdsum
• Description: At89c51cc02, T89c51cc02 Enhanced 8-bit Microcontroller With Can Controller And Flash
• Manufacturer: ATMEL Corporation

Watchdog Programming
70
AT/T89C51CC02
The three lower bits (S0, S1, S2) located into WDTPRG register permit to program the
WDT duration.
Table 50. Machine Cycle Count
To compute WD Timeout, the following formula is applied:
Note:
Find Hereafter computed Timeout values for f
Table 51. Timeout Computation
S2
0
0
0
0
1
1
1
1
S2
0
0
0
0
1
1
1
1
Svalue represents the decimal value of (S2 S1 S0)
FTime Out
S1
0
0
1
1
0
0
1
1
–
S1
0
0
1
1
0
0
1
1
=
---------------------------------------------------------------------------- -
6 2
×
S0
0
1
0
1
0
1
0
1
WDX2
S0
0
1
0
1
0
1
0
1
∧
X2
f
F
OSC
131.07 ms
262.14 ms
524.29 ms
osc
16.38 ms
32.77 ms
65.54 ms
(
1.05 s
2.10 s
2
=12 MHz
14
OSC
×
2
Svalue
XTAL = 12 MHz in X1 mode
)
f
Machine Cycle Count
OSC
196.56 ms
393.12 ms
786.24 ms
12.28 ms
24.57 ms
49.14 ms
98.28 ms
1.57 s
=16MHz
2
2
2
2
2
2
2
2
14
15
17
18
19
20
21
16
- 1
- 1
- 1
- 1
- 1
- 1
- 1
- 1
f
OSC
4126L–CAN–01/08
157.28 ms
314.56 ms
629.12 ms
19.66 ms
39.32 ms
78.64 ms
9.82 ms
1.25 s
=20 MHz