ATMEGA1280V-8AUR Atmel, ATMEGA1280V-8AUR Datasheet - Page 176

• Manufacturer Part Number: ATMEGA1280V-8AUR
• Description: MCU AVR 128K FLASH 8MHZ 100TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA1280V-8AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 86
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 16x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-TQFP, 100-VQFP
• For Use With: ATSTK600-TQFP100 - STK600 SOCKET/ADAPTER 100-TQFPATSTK503 - STARTER KIT AVR EXP MODULE 100P
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

19.4
2549M–AVR–09/10
Modes of Operation
Figure 19-2. Counter Unit Block Diagram
Signal description (internal signals):
Depending on the mode of operation used, the counter is cleared, incremented, or decremented
at each timer clock (clk
selected by the Clock Select bits (CS22:0). When no clock source is selected (CS22:0 = 0) the
timer is stopped. However, the TCNT2 value can be accessed by the CPU, regardless of
whether clk
count operations.
The counting sequence is determined by the setting of the WGM21 and WGM20 bits located in
the Timer/Counter Control Register (TCCR2A) and the WGM22 located in the Timer/Counter
Control Register B (TCCR2B). There are close connections between how the counter behaves
(counts) and how waveforms are generated on the Output Compare outputs OC2A and OC2B.
For more details about advanced counting sequences and waveform generation, see
Operation” on page
The Timer/Counter Overflow Flag (TOV2) is set according to the mode of operation selected by
the WGM22:0 bits. TOV2 can be used for generating a CPU interrupt.
The mode of operation, that is, the behavior of the Timer/Counter and the Output Compare pins,
is defined by the combination of the Waveform Generation mode (WGM22:0) and Compare Out-
put mode (COM2x1:0) bits. The Compare Output mode bits do not affect the counting sequence,
while the Waveform Generation mode bits do. The COM2x1:0 bits control whether the PWM out-
put generated should be inverted or not (inverted or non-inverted PWM). For non-PWM modes
the COM2x1:0 bits control whether the output should be set, cleared, or toggled at a compare
match.
For detailed timing information refer to
count
direction
clear
clk
top
bottom
See “Compare Match Output Unit” on page 182.
Tn
T2
DATA BUS
is present or not. A CPU write overrides (has priority over) all counter clear or
TCNTn
176.
T2
). clk
Increment or decrement TCNT2 by 1.
Selects between increment and decrement.
Clear TCNT2 (set all bits to zero).
Timer/Counter clock, referred to as clk
Signalizes that TCNT2 has reached maximum value.
Signalizes that TCNT2 has reached minimum value (zero).
T2
ATmega640/1280/1281/2560/2561
direction
can be generated from an external or internal clock source,
count
clear
bottom
“Timer/Counter Timing Diagrams” on page
Control Logic
top
TOVn
(Int.Req.)
clk
Tn
Prescaler
T2
in the following.
Oscillator
T/C
clk
I/O
183.
TOSC2
TOSC1
“Modes of
176