NEC PD78F9488 - Manual (Page 161)

User’s Manual U15331EJ4V1UD
161
CHAPTER 8 WATCH TIMER
8.1 Watch Timer Functions
The watch timer has the following functions.
• Watch timer
• Interval timer
The watch and interval timers can be used at the same time.
Figure 8-1 shows a block diagram of the watch timer.
Figure 8-1. Block Diagram of Watch Timer
f
X
/2 7
f
XT
/2
f XT
Selector
Selector
f
W
f W
2 4
f W
2 5
f W
2 6
f W
2 7
f W
2 8
f W
2 9
Clear
9-bit prescaler
Selector
Clear
5-bit counter INTWT
INTWTI
WTM7 WTS WTM6 WTM5 WTM4 WTM1 WTM0
Watch timer mode
control register (WTM) Watch timer interrupt
time selection
register (WTIM)
Internal bus
1/2