Operation - Panasonic F77G User Manual

Chapter 6 8-bit Timers
6-9 Simple Pulse Width Measurement
6-9-1

Operation

Timer measures the "L" duration of the pulse signal input from the external interrupt pin.
Simple Pulse Width Measurement Operation by 8-bit Timer (Timers 0, 4 and 5)
During the input signal of the external interrupt pin (simple pulse width) is "L", the binary counter of the
timer counts up. Pulse width "L" period can be measured by reading the count of timer. 8-bit timers that
have the simple pulse width measurement function are timers 0, 4 and 5.
Table 6-9-1
Simple pulse width
measurement enable pin
Count Timing of Simple Pulse Width Measurement (Timer 0, Timer 4, Timer 5)
Count
clock source
External
interrupt
IRQ(n/2+2)
TMnEN
flag
Compare
regster
Binary
counter
Figure 6-9-1
During the input signal of the external interrupt pin for simple pulse width measurement is "L" at
TMnEN flag operation ("1"), timer counts up.
VI - 36
Simple Pulse Width Measurement
Simple Pulse Width Measurement Able Pins (Timers 0, 4 and 5)
Timer 0
External interrupt 2
(P22/IRQ2)
00
Count Timing at Measurement of Simple Pulse Width
(Timer 0, Timer 4, Timer 5))
Timer 4
External interrupt 4 External interrupt 5
(P24/IRQ4)
FF
01 02 03
Timer 5
(P23/IRQ3)
04