• Output compare timing
The compare match signal is generated in the last state in which TCNT and the general register
match (when TCNT changes from the matching value to the next value). When the compare
match signal is generated, the output value selected in TIOR is output at the output compare
pin (TIOCA or TIOCB). When TCNT matches a general register, the compare match signal is
not generated until the next counter clock pulse.
Figure 8-22 shows the output compare timing.
ø
TCNT input
clock
TCNT
GR
Compare
match signal
TIOCA,
TIOCB
Input Capture Function: The TCNT value can be captured into a general register when a
transition occurs at an input capture/output compare pin (TIOCA or TIOCB). Capture can take
place on the rising edge, falling edge, or both edges. The input capture function can be used to
measure pulse width or period.
• Sample setup procedure for input capture
Figure 8-23 shows a sample procedure for setting up input capture.
N
N
Figure 8-22 Output Compare Timing
N + 1
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