upd70f3017ay Renesas Electronics Corporation., upd70f3017ay Datasheet - Page 212

• Manufacturer Part Number: upd70f3017ay
• Description: V850/sa1tm 32-/16-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

8.4.3 Cautions
(WTM1 and WTM0 bits of watch timer mode control register (WTM) = 1, 1).
212
Figure 8-3. Example of Generation of Watch Timer Interrupt Request (INTWT) (When Interrupt Period = 0.5 s)
Remark
Some time is required before the first watch timer interrupt request (INTWT) is generated after operation is enabled
It takes 0.515625 seconds for the first INTWT to be generated (2
generated every 0.5 seconds.
interrupt INTWTI
Count clock f
interrupt INTWT
f
( ): f
n: Interval timer operation count
Interval timer
W
Watch timer
: Watch timer clock frequency
W
= 32.768 kHz
5-bit counter
f
W
W
/2
or
9
WTM0 = 1
WTM1 = 1
INTWT
Figure 8-2. Operation Timing of Watch Timer/Interval Timer
Start
0H
Interrupt time of watch timer (0.5 s)
Interval time
(T)
CHAPTER 8 WATCH TIMER
0.515625 s
User’s Manual U12768EJ4V1UD
nT
0.5 s
Overflow
Interrupt time of watch timer (0.5 s)
9
Interval time
× 1/32.768 = 0.015625 s). INTWT is then
(T)
0.5 s
nT
Overflow