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Chapter 6 8-bit Timers
VI - 36
Simple Pulse Width Measurement
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.
Count Timing of Simple Pulse Width Measurement (Timer 0, Timer 4, Timer 5)
During the input signal of the external interrupt pin for simple pulse width measurement is "L" at
TMnEN flag operation ("1"), timer counts up.
Table 6-9-1 Simple Pulse Width Measurement Able Pins (Timers 0, 4 and 5)
Figure 6-9-1 Count Timing at Measurement of Simple Pulse Width
(Timer 0, Timer 4, Timer 5))
04
FF
00 01 02
03
Count
clock source
TMnEN
flag
Compare
regster
Binary
counter
External
interrupt
IRQ(n/2+2)
Ti mer 0 Ti mer 4 Ti mer 5
Simple pulse width
measurement enable pin
External interrupt 2
(P22/IRQ2)
External interrupt 4
(P24/IRQ4)
External interrupt 5
(P23/IRQ3)