Operation Of Pulse Width Measurement Function - Fujitsu MB90335 Series Hardware Manual

CHAPTER 13 PWC TIMER
13.3 Movement of PWC Timer
13.3.2

Operation of Pulse Width Measurement Function

Time cycle between arbiter events of input pulse can be measured by the time.
■ Operation of Pulse Width Measurement Function
The pulse width measurement function does not start the count until the set measurement start edge is input
after it is started. Starts the count up after clearing the timer to be 0000
stops the count when detecting the stop edge. The value counted in this period is registered as the pulse
width. When the measurement ends, the interruption is detected.
Operates as follows depending on the measurement mode after the measurement.
• Single measurement mode: Suspends the operation.
• Continuous measurement mode:The timer value is transferred to the buffer register and the
Figure 13.3-2 and Figure 13.3-3 show the single measurement mode operation and the continuous measurement
mode operation, respectively.
Figure 13.3-2 Pulse Width Measurement Operation (Single Measurement Mode/ "H" Width Measurement)
PWC input measured pulse
Timer count value
FFFF
H
0000
H
Figure 13.3-3 Pulse Width Measurement Operation (Continuous Measurement Mode/ "H" Width
PWC input measured pulse
Timer count value
FFFF
H
0000
H
Measurement
302
measurement is suspended until the next start edge is input.
Timer clear
Measurement Timer Timer
start start stop
EDIR flag set (Measurement end)
Measurement)
Transfer data to PWCR
Timer clear
Timer Timer
start start stop
EDIR flag set (Measurement end)
FUJITSU MICROELECTRONICS LIMITED
(A sold line shows the timer count value.)
(A solid line shows the timer count value.)
Overflow
Timer clear
Timer
start
EDIR flag set
MB90335 Series
when detecting the start edge and
H
Time
Time
CM44-10137-6E