Fujitsu MB90460 Series Hardware Manual page 467

CHAPTER 16 PWC Timer
Timer count value
FFFF
H
PWC write value
0000
H
Write to PWC
OVIR flag setting
POUT bit
If the timer is started at L level, the level is not toggled when the timer is restarted
(except when an overflow occurs simultaneously)
■ Pulse-width Measurement Function
The pulse-width measurement function calculates the time between the specified events related to the input
pulse.
When this function is activated, a count is started after the specified count start edge is input. If the counter
is cleared to "0000
count value during this period is held in the register as the pulse width.
When the measurement terminates or an overflow occurs, an interrupt request can be generated. When the
measurement is completed, the following occurs:
• Single measurement mode
The operation is discontinued (see Figure 16.6-3).
• Continuous measurement mode
The timer value is transferred to the buffer register and the timer is in free-run state until the next edge is
input (see Figure 16.6-4).
448
Figure 16.6-2 Timer Operation (Reload Mode)
Overflow
Overflow
Reload
Reload
Reload
Timer starts
", a count is started when the start edge is detected, then the stop edge is detected. The
H
Overflow
Overflow
Reload
Reload
Reload
Restart
Overflow
(Restart is invalid)
Reload
Timer stop
Time