Operations Of The Pulse Width Measurement Function - Fujitsu F2MC-16LX Hardware Manual

CHAPTER 14 PWC TIMER

14.3.2 Operations of the Pulse Width Measurement Function

With this function, the timer can be used to measure the time interval between any
input pulse events.
I Operations of the pulse width measurement function
After the start of the pulse width measurement function, counting does not start before the
specified measurement start edge is input. The timer is cleared to 0000
is detected, and counting starts. Counting stops when a stop edge is detected. The counter
value during this period is stored in the register. The end of measurement is detected by an
interrupt.
After measurement ends, the following operations are performed depending on the
measurement mode:
• In one-shot measurement mode: Operation is interrupted.
• In repeated measurement mode: The timer value is transferred to the buffer register and the
measurement is suspended until input of the next start edge.
Figure 14.3-2 "Pulse width measurement operation (one-shot measurement mode/"H"-level
pulse width measurement)" shows the operation in one-shot measurement mode. Figure 14.3-3
"Pulse width measurement operation (repeated measurement mode/"H"-level pulse width
measurement)" shows the operation in repeated measurement mode.
(one-shot measurement mode/"H"-level pulse width measurement)
PWC input pulses
to be measured
Timer count value
FFFF
H
0000
H
Measurement
starts
286
Figure 14.3-2 Pulse width measurement operation
Timer clear
Timer
Timer stop
start
EDIR flag set (measurement end)
whenever a start edge
H
(Solid line indicates timer count value)
Time