ATMEGA8-16PI Atmel, ATMEGA8-16PI Datasheet - Page 114

• Manufacturer Part Number: ATMEGA8-16PI
• Description: IC AVR MCU 8K 16MHZ IND 28-DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8-16PI

• 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: 23
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: ATMEGA816PI

8-bit
Timer/Counter
Register
Description
Timer/Counter Control
Register – TCCR2
114
ATmega8(L)
Figure 55
Figure 55. Timer/Counter Timing Diagram, Clear Timer on Compare Match Mode, with Pres-
caler (f
• Bit 7 – FOC2: Force Output Compare
The FOC2 bit is only active when the WGM bits specify a non-PWM mode. However, for ensur-
ing compatibility with future devices, this bit must be set to zero when TCCR2 is written when
operating in PWM mode. When writing a logical one to the FOC2 bit, an immediate Compare
Match is forced on the waveform generation unit. The OC2 output is changed according to its
COM21:0 bits setting. Note that the FOC2 bit is implemented as a strobe. Therefore it is the
value present in the COM21:0 bits that determines the effect of the forced compare.
A FOC2 strobe will not generate any interrupt, nor will it clear the timer in CTC mode using
OCR2 as TOP.
The FOC2 bit is always read as zero.
• Bit 6:3 – WGM21:0: Waveform Generation Mode
These bits control the counting sequence of the counter, the source for the maximum (TOP)
counter value, and what type of waveform generation to be used. Modes of operation supported
by the Timer/Counter unit are: Normal mode, Clear Timer on Compare Match (CTC) mode, and
two types of Pulse Width Modulation (PWM) modes. See
Operation” on page
Bit
Read/Write
Initial Value
TCNTn
(clk
OCRn
(CTC)
OCFn
clk
clk
clk_I/O
I/O
I/O
Tn
shows the setting of OCF2 and the clearing of TCNT2 in CTC mode.
/8)
/8)
FOC2
W
7
0
108.
WGM20
R/W
TOP - 1
6
0
COM21
R/W
5
0
COM20
R/W
0
4
TOP
WGM21
R/W
3
0
TOP
CS22
R/W
2
0
Table 42 on page 115
BOTTOM
CS21
R/W
1
0
CS20
R/W
0
0
BOTTOM + 1
TCCR2
and
2486Z–AVR–02/11
“Modes of