Rainbow Electronics ATmega128RFA1 - Manual (Page 320)

320
8266A-MCU Wireless-12/09
ATmega128RFA1
Figure 21-9 below shows the same timing data, but with the prescaler enabled.
Figure 21-9. Timer/Counter Timing Diagram, with Prescaler (f
clk_I/O
/8)
TOVn
TCNTn MAX - 1 MAX BOTTOM BOTTOM + 1
clk
I/O
clk
Tn
(clk
I/O
/8)
Figure 21-10 below shows the setting of OCF2A in all modes except CTC mode.
Figure 21-10. Timer/Counter Timing Diagram, Setting of OCF2A, with Prescaler
(f
clk_I/O
/8)
OCFnx
OCRnx
TCNTn
OCRnx Value
OCRnx - 1 OCRnx OCRnx + 1 OCRnx + 2
clk
I/O
clk
Tn
(clk
I/O
/8)
Figure 21-11 below shows the setting of OCF2A and the clearing of TCNT2 in CTC
mode.
Figure 21-11. Timer/Counter Timing Diagram, Clear Timer on Compare Match mode,
with Prescaler (f
clk_I/O
/8)
OCFnx
OCRnx
TCNTn
(CTC)
TOP
TOP - 1 TOP BOTTOM BOTTOM + 1
clk
I/O
clk
Tn
(clk
I/O
/8)
21.9 Asynchronous Operation of Timer/Counter2
When Timer/Counter2 operates asynchronously, some considerations must be taken.