Datasheet

Section 12 8-Bit Timers
Rev. 4.00 Sep 27, 2006 page 364 of 1130
REJ09B0327-0400
Timer Output Timing
When compare-match A or B occurs, the timer output changes as specified by the output select
bits (OS3 to OS0) in TCSR. Depending on these bits, the output can remain the same, be set to 0,
be set to 1, or toggle.
Figure 12.5 shows the timing when the output is set to toggle at compare-match A.
φ
Compare-match A
signal
Timer output
pin
Figure 12.5 Timing of Timer Output
Timing of Compare-Match Clear
TCNT is cleared when compare-match A or B occurs, depending on the setting of the CCLR1 and
CCLR0 bits in TCR. Figure 12.6 shows the timing of this operation.
φ
N H'00
Compare-match
signal
TCNT
Figure 12.6 Timing of Compare-Match Clear
12.3.3 TCNT External Reset Timing
TCNT is cleared at the rising edge of an external reset input, depending on the settings of the
CCLR1 and CCLR0 bits in TCR. The width of the clearing pulse must be at least 1.5 states. Figure
12.7 shows the timing of this operation.