at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 53

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

8.1.6
8.2
8.2.1
7734M–AVR–03/10
System Control registers
Watchdog Reset
MCU Status Register – MCUSR
Figure 8-5.
When the Watchdog times out, it will generate a short reset pulse of one CK cycle duration. On the falling
edge of this pulse, the delay timer starts counting the Time-out period t
on operation of the Watchdog Timer.
Figure 8-6.
The MCU Status Register provides information on which reset source caused an MCU reset.
• Bit 3 – WDRF: Watchdog Reset Flag
This bit is set if a Watchdog Reset occurs. The bit is reset by a Power-on Reset, or by writing a logic zero
to the flag.
Bit
Read/Write
Initial Value
7
–
R
0
Brown-out Reset During Operation
Watchdog Reset During Operation
CC
INTERNAL
TIME-OUT
RESET
RESET
V
CC
6
–
R
0
0
5
–
R
4
–
R
0
V
CK
BOT-
3
WDRF
R/W
See Bit Description
2
BORF
R/W
TOUT
V
t
TOUT
BOT+
1
EXTRF
R/W
. Refer to
AT90PWM81
0
PORF
R/W
page 55
for details
MCUSR
53