ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 115

• Manufacturer Part Number: ATMEGA169
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Timer/Counter Timing
Diagrams
2514P–AVR–07/06
The Timer/Counter is a synchronous design and the timer clock (clk
shown as a clock enable signal in the following figures. The figures include information
on when Interrupt Flags are set, and when the OCR1x Register is updated with the
OCR1x buffer value (only for modes utilizing double buffering). Figure 49 shows a timing
diagram for the setting of OCF1x.
Figure 49. Timer/Counter Timing Diagram, Setting of OCF1x, no Prescaling
Figure 50 shows the same timing data, but with the prescaler enabled.
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.
TCNTn
OCRnx
OCFnx
(clk
TCNTn
OCRnx
OCFnx
(clk
clk
clk
clk
clk
I/O
I/O
I/O
Tn
I/O
Tn
/1)
/8)
OCRnx - 1
OCRnx - 1
OCRnx
OCRnx
OCRnx Value
OCRnx Value
OCRnx + 1
OCRnx + 1
ATmega169/V
T1
OCRnx + 2
OCRnx + 2
) is therefore
clk_I/O
115
/8)