ATMEGA64-16AI Atmel, ATMEGA64-16AI Datasheet - Page 95

• Manufacturer Part Number: ATMEGA64-16AI
• Description: IC AVR MCU 64K 16MHZ IND 64-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA64-16AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Counter Unit
Output Compare
Unit
2490Q–AVR–06/10
The main part of the 8-bit Timer/Counter is the programmable bi-directional counter unit.
35
Figure 35. 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 (CS02:0). When no clock source is selected (CS02:0 = 0) the
timer is stopped. However, the TCNT0 value can be accessed by the CPU, regardless of
whether clk
count operations.
The counting sequence is determined by the setting of the WGM01 and WGM00 bits located in
the Timer/Counter Control Register (TCCR0). There are close connections between how the
counter behaves (counts) and how waveforms are generated on the Output Compare output
OC0. For more details about advanced counting sequences and waveform generation, see
“Modes of Operation” on page
The Timer/Counter Overflow Flag (TOV0) is set according to the mode of operation selected by
the WGM01:0 bits.
The 8-bit comparator continuously compares TCNT0 with the Output Compare Register
(OCR0). Whenever TCNT0 equals OCR0, the comparator signals a match. A match will set the
Output Compare Flag (OCF0) at the next timer clock cycle. If enabled (OCIE0 = 1), the Output
Compare Flag generates an Output Compare interrupt. The OCF0 flag is automatically cleared
when the interrupt is executed. Alternatively, the OCF0 flag can be cleared by software by writ-
ing a logical one to its I/O bit location. The Waveform Generator uses the match signal to
generate an output according to operating mode set by the WGM01:0 bits and Compare Output
mode (COM01:0) bits. The max and bottom signals are used by the Waveform Generator for
handling the special cases of the extreme values in some modes of operation
ation” on page
count
direction
clear
clk
top
bottom
shows a block diagram of the counter and its surrounding environment.
T0
DATA BUS
T0
TCNTn
Increment or decrement TCNT0 by 1.
Selects between increment and decrement.
Clear TCNT0 (set all bits to zero).
Timer/Counter clock.
Signalizes that TCNT0 has reached maximum value.
Signalizes that TCNT0 has reached minimum value (zero).
is present or not. A CPU write overrides (has priority over) all counter clear or
98).
TOV0
Figure 36
T0
can be used for generating a CPU interrupt.
). clk
direction
shows a block diagram of the Output Compare unit.
count
clear
98.
bottom
T0
can be generated from an external or internal clock source,
Control Logic
top
TOVn
(Int.Req.)
clk
Tn
Prescaler
ATmega64(L)
Oscillator
T/C
clk
(“Modes of Oper-
I/O
TOSC2
TOSC1
Figure
95