ATTIny2313-16MI ATMEL Corporation, ATTIny2313-16MI Datasheet - Page 37

• Manufacturer Part Number: ATTIny2313-16MI
• Description: 8-bit AVR Microcontroller with 2K Bytes In-System Programmable Flash
• Manufacturer: ATMEL Corporation

Watchdog Reset
MCU Status Register –
MCUSR
2543C–AVR–12/03
When the Watchdog times out, it will generate a short reset pulse of one CK cycle dura-
tion. On the falling edge of this pulse, the delay timer starts counting the Time-out period
t
Figure 19. Watchdog Reset During Operation
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 2 – BORF: Brown-out Reset Flag
This bit is set if a Brown-out Reset occurs. The bit is reset by a Power-on Reset, or by
writing a logic zero to the flag.
• Bit 1 – EXTRF: External Reset Flag
This bit is set if an External Reset occurs. The bit is reset by a Power-on Reset, or by
writing a logic zero to the flag.
• Bit 0 – PORF: Power-on Reset Flag
This bit is set if a Power-on Reset occurs. The bit is reset only by writing a logic zero to
the flag.
To make use of the Reset flags to identify a reset condition, the user should read and
then reset the MCUSR as early as possible in the program. If the register is cleared
before another reset occurs, the source of the reset can be found by examining the reset
flags.
TOUT
Bit
Read/Write
Initial Value
. Refer to page 44 for details on operation of the Watchdog Timer.
CC
R
7
–
0
R
6
–
0
R
5
–
0
CK
R
4
–
WDRF
R/W
3
See Bit Description
BORF
R/W
2
ATtiny2313/V
EXTRF
R/W
1
PORF
R/W
0
MCUSR
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