ATMEGA325-16AJ ATMEL [ATMEL Corporation], ATMEGA325-16AJ Datasheet - Page 116

• Manufacturer Part Number: ATMEGA325-16AJ
• Description: 8-bit Microcontroller with In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

116
ATmega325/3250/645/6450
Figure 50. Timer/Counter Timing Diagram, Setting of OCF1x, with Prescaler (f
Figure 51 shows the count sequence close to TOP in various modes. When using phase
and frequency correct PWM mode the OCR1x Register is updated at BOTTOM. The
timing diagrams will be 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 51. Timer/Counter Timing Diagram, no Prescaling
Figure 52 shows the same timing data, but with the prescaler enabled.
(PC and PFC PWM)
and ICFn
OCRnx
(CTC and FPWM)
TCNTn
OCFnx
(clk
TOVn
(Update at TOP)
clk
clk
I/O
TCNTn
TCNTn
OCRnx
(clk
as TOP)
I/O
Tn
clk
clk
/8)
I/O
(FPWM)
I/O
Tn
/1)
(if used
OCRnx - 1
TOP - 1
TOP - 1
Old OCRnx Value
OCRnx
OCRnx Value
TOP
TOP
OCRnx + 1
BOTTOM
TOP - 1
New OCRnx Value
OCRnx + 2
BOTTOM + 1
2570A–AVR–09/04
TOP - 2
clk_I/O
/8)