ATMEGA649A-AU Atmel, ATMEGA649A-AU Datasheet - Page 108

• Manufacturer Part Number: ATMEGA649A-AU
• Description: IC MCU AVR 64K FLASH 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA649A-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 54
• 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): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

14.9
14.9.1
8284A–AVR–10/10
Register Description
TCCR0A – Timer/Counter Control Register A
Figure 14-10. Timer/Counter Timing Diagram, Setting of OCF0A, with Prescaler (f
Figure 14-11
Figure 14-11. Timer/Counter Timing Diagram, Clear Timer on Compare Match mode, with Pres-
• Bit 7 – FOC0A: Force Output Compare A
The FOC0A bit is only active when the WGM00 bit specifies a non-PWM mode. However, for
ensuring compatibility with future devices, this bit must be set to zero when TCCR0A is written
when operating in PWM mode. When writing a logical one to the FOC0A bit, an immediate com-
pare match is forced on the Waveform Generation unit. The OC0A output is changed according
to its COM0A1:0 bits setting. Note that the FOC0A bit is implemented as a strobe. Therefore it is
the value present in the COM0A1:0 bits that determines the effect of the forced compare.
A FOC0A strobe will not generate any interrupt, nor will it clear the timer in CTC mode using
OCR0A as TOP.
The FOC0A bit is always read as zero.
Bit
0x24 (0x44)
Read/Write
Initial Value
ATmega169A/169PA/329A/329PA/649A/649P/3290A/3290PA/6490A/6490P
TCNTn
TCNTn
(clk
(clk
OCRnx
OCFnx
(CTC)
OCRnx
OCFnx
clk
clk
clk
clk
I/O
I/O
I/O
I/O
Tn
Tn
/8)
/8)
shows the setting of OCF0A and the clearing of TCNT0 in CTC mode.
caler (f
FOC0A
W
7
0
clk_I/O
WGM00
OCRnx - 1
TOP - 1
R/W
6
0
/8)
COM0A1
R/W
5
0
COM0A0
R/W
OCRnx
TOP
4
0
OCRnx Value
WGM01
TOP
R/W
3
0
CS02
OCRnx + 1
BOTTOM
R/W
2
0
CS01
R/W
1
0
BOTTOM + 1
CS00
OCRnx + 2
R/W
0
0
clk_I/O
/8)
TCCR0A
108