atmega161-4pi ATMEL Corporation, atmega161-4pi Datasheet - Page 28

• Manufacturer Part Number: atmega161-4pi
• Description: 8-bit Microcontroller With 16k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

External Reset
Watchdog Reset
28
ATmega161(L)
An External Reset is generated by a low level on the RESET pin. Reset pulses longer
than 500 ns will generate a Reset, even if the clock is not running. Shorter pulses are
not guaranteed to generate a Reset. When the applied signal reaches the Reset
Threshold Voltage (V
Time-out period (t
Figure 27. External Reset during Operation
When the Watchdog times out, it will generate a short reset pulse of 1 XTAL cycle dura-
tion. On the falling edge of this pulse, the delay timer starts counting the Time-out period
(t
Figure 28. Watchdog Reset during Operation
TOUT
). Refer to page 58 for details on operation of the Watchdog.
TOUT
RST
) has expired.
) on its positive edge, the delay timer starts the MCU after the
1228D–AVR–02/07