ATTIny2313-16MI ATMEL Corporation, ATTIny2313-16MI Datasheet - Page 39

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

Watchdog Timer Control
Register – WDTCR
2543C–AVR–12/03
Figure 20. Watchdog Timer
• Bit 7 – WDIF: Watchdog Timeout Interrupt Flag
This bit is set when a time-out occurs in the Watchdog Timer and the Watchdog Timer is
configured for interrupt. WDIF is cleared by hardware when executing the corresponding
interrupt handling vector. Alternatively, WDIF is cleared by writing a logic one to the flag.
When the I-bit in SREG and WDIE are set, the Watchdog Time-out Interrupt is
executed.
• Bit 6 – WDIE: Watchdog Timeout Interrupt Enable
When this bit is written to one, WDE is cleared, and the I-bit in the Status Register is set,
the Watchdog Time-out Interrupt is enabled. In this mode the corresponding interrupt is
executed instead of a reset if a timeout in the Watchdog Timer occurs.
If WDE is set, WDIE is automatically cleared by hardware when a time-out occurs. This
is useful for keeping the Watchdog Reset security while using the interrupt. After the
WDIE bit is cleared, the next time-out will generate a reset. To avoid the Watchdog
Reset, WDIE must be set after each interrupt.
Table 20. Watchdog Timer Configuration
• Bit 4 – WDCE: Watchdog Change Enable
This bit must be set when the WDE bit is written to logic zero. Otherwise, the Watchdog
will not be disabled. Once written to one, hardware will clear this bit after four clock
cycles. Refer to the description of the WDE bit for a Watchdog disable procedure. This
Bit
Read/Write
Initial Value
WDE
0
0
1
1
WDIF
WDIE
R/W
7
0
0
1
0
1
WATCHDOG
WDIE
OSCILLATOR
R/W
6
0
Watchdog Timer State
Stopped
Running
Running
Running
RESET
128 kHz
WDP0
WDP1
WDP2
WDP3
WDE
WDP3
R/W
5
0
WDCE
R/W
4
0
WDE
R/W
X
3
MCU RESET
PRESCALER
WATCHDOG
WDP2
R/W
2
0
Action on Time-out
None
Interrupt
Reset
Interrupt
ATtiny2313/V
WDP1
R/W
1
0
WDP0
R/W
0
0
WDTCR
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