11.1.2
Block Diagram
Figure 11.1 shows a block diagram of the WDT.
Interrupt signal
(interval timer)
Reset
(internal, external)
Legend:
TCNT:
Timer counter
TCSR:
Timer control/status register
RSTCSR:
Reset control/status register
11.1.3
Pin Configuration
Table 11.1 describes the WDT output pin.
Table 11.1 WDT Pin
Name
Abbreviation
RESO
Reset output
Note: * Open-drain output.
300
Overflow
Interrupt
control
RSTCSR
Reset control
Clock
Figure 11.1 WDT Block Diagram
I/O
Function
Output*
External output of the watchdog timer reset signal
TCNT
TCSR
Clock
selector
Internal
data bus
Read/
write
control
Internal clock sources
φ/2
φ/32
φ/64
φ/128
φ/256
φ/512
φ/2048
φ/4096