Datasheet

60
7799D–AVR–11/10
ATmega8U2/16U2/32U2
Table 10-5. Watchdog Timer Prescale Select, DIV = 2 (CLKwdt = CLK128 / 5)
WDP3 WDP2 WDP1 WDP0
Number of WDT Oscillator
Cycles before 1st time-out
(Early warning)
Early warning Typical
Time-out at
V
CC
= 5.0V
Watchdog
Reset/Interrupt Typical
Time-out at
V
CC
= 5.0V
0 0 0 0 2K (2048) cycles 80 ms 160 ms
0 0 0 1 4K (4096) cycles 160 ms 320 ms
0 0 1 0 8K (8192) cycles 320 ms 640 ms
0 0 1 1 16K (16384) cycles 0.625 s 1.25 s
0 1 0 0 32K (32768) cycles 1.25 s 2.5 s
0 1 0 1 64K (65536) cycles 2.5 s 5 s
0 1 1 0 128K (131072) cycles 5 s 10 s
0 1 1 1 256K (262144) cycles 10 s 20 s
1 0 0 0 512K (524288) cycles 20 s 40 s
1 0 0 1 1024K (1048576) cycles 40 s 80 s
1010
Reserved
1011
1100
1101
1110
1111
Table 10-6. Watchdog Timer Prescale Select, DIV = 3 (CLKwdt = CLK128 / 7)
WDP3 WDP2 WDP1 WDP0
Number of WDT Oscillator
Cycles before 1st time-out
(Early warning)
Early warning Typical
Time-out at
V
CC
= 5.0V
Watchdog
Reset/Interrupt Typical
Time-out at
V
CC
= 5.0V
0 0 0 0 2K (2048) cycles 112 ms 224 ms
0 0 0 1 4K (4096) cycles 224 ms 448 ms
0 0 1 0 8K (8192) cycles 448 ms 896 ms
0 0 1 1 16K (16384) cycles 0.875 s 1.75 s
0 1 0 0 32K (32768) cycles 1.75 s 3.5 s
0 1 0 1 64K (65536) cycles 3.5 s 7 s
0 1 1 0 128K (131072) cycles 7 s 14 s
0 1 1 1 256K (262144) cycles 14 s 28 s
1 0 0 0 512K (524288) cycles 28 s 56 s
1 0 0 1 1024K (1048576) cycles 56 s 112 s