•
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 10-22 shows the output compare timing.
Figure 10-22 Output Compare Timing
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 10-23 shows a sample procedure for setting up input capture.
N + 1
N
N
ø
TCNT input
clock
TCNT
GR
Compare
match signal
TIOCA,
TIOCB
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