User’s Manual U15109EJ3V0UD
309
CHAPTER 9 WATCH TIMER FUNCTION
9.1 Function
The watch timer has the following functions.
•
Watch timer
•
Interval timer
The watch timer and interval timer functions can be used at the same time.
Figure 9-1. Block Diagram of Watch Timer
f
XX
f
W
/2
4
f
W
/2
5
f
W
/2
6
f
W
/2
7
f
W
/2
8
f
W
/2
10
f
W
/2
11
f
W
/2
9
f
XT
4
INTWTN
INTWTNI
WTNM0
WTNM1
WTNM2
WTNM3
WTNM4
WTNM5
WTNM6
WTNM7
WTNCS0
WTNCS1
WTNCS2
f
W
Clear
Clear
Internal bus
Watch timer mode control
register (WTNM)
Watch timer high-speed clock
select register (WTNHC)
Watch timer clock select
register (WTNCS)
5-bit counter
Selector
Selector
Selector
Selector
11-bit prescaler
Remark
f
XX
: Main clock frequency
f
XT
:
Subclock frequency
f
W
:
Watch timer clock frequency