Figure 10-16 Periodic Counter Operation
•
TCNT count timing
— Internal clock source
Bits TPSC2 to TPSC0 in TCR select the system clock (ø) or one of three internal clock
sources obtained by prescaling the system clock (ø/2, ø/4, ø/8).
Figure 10-17 shows the timing.
Figure 10-17 Count Timing for Internal Clock Sources
TCNT value
GR
H'0000
STR bit
IMF
Time
Counter cleared by general
register compare match
ø
TCNT input
TCNT
Internal
clock
N – 1
N
N + 1
339
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