
Initial State
(watchdog
disabled)
(TIMn=x)
(PRDn=x)
Other than A5C6h
to WDKEY
TIMMODE=2h
TIM12RS=1
TIM34RS=1
Power-up/Reset
(hardware/software)
Pre-active
state
WDEN=1;
A5C6h to
WDKEY
WDKEY
A5C6h to
DA7Eh to
WDKEY
(counter cleared,
WDFLAG cleared)
Other than DA7Eh
or A5C6h to
WDKEY
Timeout
state
(watchdog
disabled)
Active
state
(waiting for
A5C6h)
Other than A5C6h
or DA7Eh to WDKEY
(WDFLAG set,
WDTINT triggered)
Timeout
(WDFLAG set,
WDTINT triggered)
Service
state
(counter
counts up)
(waiting for
DA7Eh)
A5C6h to WDKEY
DA7Eh to
WDKEY
(counter
cleared)
Time out
(WDFLAG set,
WDTINT triggered)
Other than DA7Eh
or A5C6h to WDKEY
(WDFLAG set,
WDTINT triggered)
A5C6h to
WDKEY
Disabled
state
Internal clock
Input clock
64-bit timer counter
64-bit tmer period
Equality comparator
TIM34
PRD34
TIM12
PRD12
Watchdog logic
and
pulse generator
CLKSRC12 = 0
WDEN, WDKEY
Device-level reset
Introduction
1482
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
64-Bit Timer Plus
Figure 30-9. Watchdog Timer Mode Block Diagram
Figure 30-10. Watchdog Timer Operation State Diagram