ATmega128A Atmel Corporation, ATmega128A Datasheet - Page 159

• Manufacturer Part Number: ATmega128A
• Manufacturer: Atmel Corporation

Specifications of ATmega128A

• Flash (kbytes): 128 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 53
• Ext Interrupts: 8
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 4
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 8
• Input Capture Channels: 2
• Pwm Channels: 7
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

17.9
17.9.1
8151H–AVR–02/11
Register Description
TCCR2 - Timer/Counter Control Register
Figure 17-11. Timer/Counter Timing Diagram, Clear Timer on Compare Match Mode, with Pres-
• Bit 7 – FOC2: Force Output Compare
The FOC2 bit is only active when the WGM20 bit specifies a non-PWM mode. However, for
ensuring 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 com-
pare 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
on page
Bit
Read/Write
Initial Value
TCNTn
(clk
OCRn
(CTC)
OCFn
clk
clk
I/O
153.
I/O
Tn
/8)
caler (f
FOC2
W
7
0
clk_I/O
WGM20
TOP - 1
R/W
/8)
6
0
COM21
R/W
5
0
COM20
R/W
TOP
4
0
WGM21
TOP
R/W
3
0
Table 17-2
CS22
R/W
BOTTOM
2
0
and
CS21
ATmega128A
R/W
1
0
“Modes of Operation”
BOTTOM + 1
CS20
R/W
0
0
TCCR2
159