ATMEGA162V-1AC Atmel, ATMEGA162V-1AC Datasheet - Page 117

• Manufacturer Part Number: ATMEGA162V-1AC
• Description: IC MCU AVR 16K 1.8V 8MHZ 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA162V-1AC

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 1MHz
• Connectivity: EBI/EMI, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Data Converters: -

2513C–AVR–09/02
Figure 51. CTC Mode, Timing Diagram
An interrupt can be generated at each time the counter value reaches the TOP value by
either using the OCFnA or ICFn flag according to the register used to define the TOP
value. If the interrupt is enabled, the interrupt handler routine can be used for updating
the TOP value. However, changing the TOP to a value close to BOTTOM when the
counter is running with none or a low prescaler value must be done with care since the
CTC mode does not have the double buffering feature. If the new value written to
OCRnA or ICRn is lower than the current value of TCNTn, the counter will miss the com-
pare match. The counter will then have to count to its maximum value (0xFFFF) and
wrap around starting at 0x0000 before the compare match can occur. In many cases
this feature is not desirable. An alternative will then be to use the fast PWM mode using
OCRnA for defining TOP (WGMn3:0 = 15) since the OCRnA then will be double
buffered.
For generating a waveform output in CTC mode, the OCnA output can be set to toggle
its logical level on each compare match by setting the Compare Output mode bits to tog-
gle mode (COMnA1:0 = 1). The OCnA value will not be visible on the port pin unless the
data direction for the pin is set to output (DDR_OCnA = 1). The waveform generated will
have a maximum frequency of f
The waveform frequency is defined by the following equation:
The N variable represents the prescaler factor (1, 8, 64, 256, or 1024). For
Timer/Counter3 also prescaler factors 16 and 32 are available.
As for the Normal mode of operation, the TOVn flag is set in the same timer clock cycle
that the counter counts from MAX to 0x0000.
TCNTn
OCnA
(Toggle)
Period
1
f
OCnA
OC
2
n
=
A
= f
-------------------------------------------------- -
2 N
clk_I/O
3
f
clk_I/O
1
/2 when OCRnA is set to zero (0x0000).
+
OCRnA
ATmega162(V/U/L)
4
OCnA Interrupt Flag Set
or ICFn Interrupt Flag Set
(Interrupt on TOP)
(COMnA1:0 = 1)
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