Cautions - NEC V850ES/F 3-L Series User Manual

Chapter 13
5-bit counter
Count clock
f or f
W W
Watch timer interrupt
INTWT
Interval timer interrupt
INTWTI
Figure 13-2
Note

13.4.3 Cautions

Figure 13-3
384
0H
Start
9
/2
Interrupt time of watch timer (0.5 s) Interrupt time of watch timer (0.5 s)
Interval time (T)
Operation Timing of Watch Timer/Interval Timer
f : Watch Timer clock frequency
W
Values in parentheses apply to operation with count clock f
n: Number of interval timer operations
The following time is required before the first Watch Timer interrupt request
signal (INTWT) is generated after operation is enabled (WTM1 and WTM0 bits
of WTM register = 1).
It takes 0.515625 seconds for the first INTWT signal to be generated
× 1/32768 = 0.015625 s longer).
9
(2
The INTWT signal is then generated every 0.5 seconds.
WTM0, WTM1
INTWT
Example of generation of Watch Timer interrupt request signal (INTWT)
(when interrupt period = 0.5 s)
User's Manual U18743EE1V2UM00
Overflow
Interval time (T)
nT
0.515625 s 0.5 s
Watch Timer Functions
Overflow
nT
= 32.768 KHz.
W
0.5 s