Operation Explanation - Fujitsu MB91260B Series Hardware Manual

CHAPTER 10 PWC (Pulse Width Count: Pulse Width Measurement)
10.4

Operation Explanation

PWC has the measurement input pin, 8-bit input division, and so on. PWC has also the
pulse width count function. Three types of count clocks can be selected. The following
describes the basic functions/operations of the pulse width count.
●
Pulse width measurement function
Enable to measure the time/cycle between any events of input pulse by the counter.
After starting, counting will not be performed until the defined measurement start edge is inputted. Start
incremental counting after the counter which detects a start edge is cleared to "0000
when a stop edge is detected. The value counted in this period is stored in the register as the pulse width.
Generate an interrupt requests when the measurement ends and an overflow occurs.
Operates as follows depending on the measurement mode after the measurement end.
•In single measurement mode: Stop operation.
•In continuous measurement mode: After transferred a counter value to the buffer register, stop the
PWC input
measured pulse
Count value
FFFF
H
0000
Start
H
measurement
PWC input
measured pulse
Count value
FFFF
H
0000
Start
H
measurement
192
Figure 10.4-1 Pulse Width Measurement Operation
(Single Measurement Mode / "H" Width Measurement)
Count clear
Count start
EDIR flag set (measurement end)
Figure 10.4-2 Pulse Width Measurement Operation
(Continuous Measurement Mode / "H" Width Measurement)
Transfer data to PWCR
Count clear
Count start
EDIR flag set (measurement end)
counting until the measurement start edge is inputted again.
Count stop
Count clear
Count start
Count stop
". Stop the counting
H
(Solid line is count value)
(Solid line is count value)
Overflow
Transfer data to PWCR
Count stop
OVIR flag set
EDIR flag set
Time
Time