Datasheet

V850ES/JG3 CHAPTER 10 WATCH TIMER FUNCTIONS
R01UH0015EJ0300 Rev.3.00 Page 393 of 870
Sep 30, 2010
Figure 10-2. Operation Timing of Watch Timer/Interval Timer
Start
Overflow Overflow
0H
Interrupt time of watch timer (0.5 s) Interrupt time of watch timer (0.5 s)
Interval time (T) Interval time (T)
nT nT
5-bit counter
Count clock
f
W or f W /2
9
Watch timer interrupt
INTWT
Interval timer interrupt
INTWTI
Remarks 1. When 0.5 seconds of the watch timer interrupt time is set.
2. f
W: Watch timer clock frequency
Values in parentheses apply to operation with fW = 32.768 kHz.
n: Number of interval timer operations
10.4.3 Cautions
Some time is required before the first watch timer interrupt request signal (INTWT) is generated after operation is
enabled (WTM.WTM1 and WTM.WTM0 bits = 1).
Figure 10-3. Example of Generation of Watch Timer Interrupt Request Signal (INTWT)
(When Interrupt Cycle = 0.5 s)
It takes 0.515625 seconds (max.) for the first INTWT signal to be generated (2
9
× 1/32768 = 0.015625 seconds
longer (max.)). The INTWT signal is then generated every 0.5 seconds.
0.5 s0.5 s0.515625 s
WTM0, WTM1
INTWT