569
WDT1 Mode Select
WDT1
WT/
IT
Description
0
Interval timer mode: WDT1 requests an interval timer interrupt (WOVI)
from the CPU when the TCNT overflows.
(Initial value)
1
Watchdog timer mode: WDT1 requests a reset or an NMI interrupt from
the CPU when the TCNT overflows.
Bit 5—Timer Enable (TME): Selects whether TCNT runs or is halted.
Bit 5
TME
Description
0
TCNT is initialized to H'00 and halted
(Initial value)
1
TCNT counts
WDT0 TCSR Bit 4—Reserved Bit: This bit is always read as 1 and cannot be modified.
WDT1 TCSR Bit 4—Prescaler Select (PSS): This bit is used to select an input clock source for
the TCNT of WDT1.
See the descriptions of Clock Select 2 to 0 for details.
WDT1 TCSR
Bit 4
PSS
Description
0
The TCNT counts frequency-division clock pulses of the ø based
prescaler (PSM).
(Initial value)
1
The TCNT counts frequency-division clock pulses of the ø SUB-based prescaler
(PSS).