ATMEGA165P_0611 Datasheet, PDF (141/368 Pages) ATMEL Corporation – 8-bit Microcontroller with 16K Bytes In-System Programmable Flash

ATmega165P
16.8 Timer/Counter Timing Diagrams
The following figures show the Timer/Counter in synchronous mode, and the timer clock (clk_T2)
is therefore shown as a clock enable signal. In asynchronous mode, clk_I/O should be replaced by
the Timer/Counter Oscillator clock. The figures include information on when Interrupt Flags are
set. Figure 16-8 contains timing data for basic Timer/Counter operation. The figure shows the
count sequence close to the MAX value in all modes other than phase correct PWM mode.
Figure 16-8. Timer/Counter Timing Diagram, no Prescaling
clk_I/O
clk_Tn
(clk_I/O/1)
TCNTn
TOVn
MAX - 1
MAX
BOTTOM
BOTTOM + 1
Figure 16-9 shows the same timing data, but with the prescaler enabled.
Figure 16-9. Timer/Counter Timing Diagram, with Prescaler (f_{clk_I/O}/8)
clk_I/O
clk_Tn
(clk_I/O/8)
TCNTn
MAX - 1
MAX
BOTTOM
BOTTOM + 1
TOVn
Figure 16-10 shows the setting of OCF2A in all modes except CTC mode.
8019H–AVR–11/06
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