Datasheet

the same, but TOP should be replaced by BOTTOM, TOP-1 by BOTTOM+1 and so on. The same
renaming applies for modes that set the TOV1 Flag at BOTTOM.
Figure 21-12. Timer/Counter Timing Diagram, no Prescaling.
TOVn (FPWM)
and ICFn (if used
as TOP)
OCRnx
(Update at TOP)
TCNTn
(CTC and FPWM)
TCNTn
(PC and PFC PWM)
TOP - 1 TOP TOP - 1 TOP - 2
Old OCRnx Value
New OCRnx Value
TOP - 1 TOP BOTTOM BOTTOM + 1
clk
Tn
(clk
I/O
/1)
clk
I/O
The next figure shows the same timing data, but with the prescaler enabled.
Figure 21-13. Timer/Counter Timing Diagram, with Prescaler (f
clk_I/O
/8)
TOVn (FPWM)
and ICFn (if used
as TOP)
OCRnx
(Update at TOP)
TCNTn
(CTC and FPWM)
TCNTn
(PC and PFC PWM)
TOP - 1
TOP TOP - 1 TOP - 2
Old OCRnx Value New OCRnx Value
TOP - 1 TOP BOTTOM BOTTOM + 1
clk
I/O
clk
Tn
(clk
I/O
/8)
21.11 Register Description
AVR 8-Bit Microcontroller
16-bit Timer/Counter1
© 2017 Microchip Technology Inc.
Datasheet Complete
40001974A-page 134