ATmega128A Atmel Corporation, ATmega128A Datasheet - Page 106

• 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

14.10 Timer/Counter Prescaler
14.11 Register Description
14.11.1
8151H–AVR–02/11
TCCR0 - Timer/Counter Control Register
Figure 14-12. Prescaler for Timer/Counter0
The clock source for Timer/Counter0 is named clk
system clock clk
from the TOSC1 pin. This enables use of Timer/Counter0 as a Real Time Counter (RTC). When
AS0 is set, pins TOSC1 and TOSC2 are disconnected from Port C. A crystal can then be con-
nected between the TOSC1 and TOSC2 pins to serve as an independent clock source for
Timer/Counter0. The Oscillator is optimized for use with a 32.768kHz crystal. Applying an exter-
nal clock source to TOSC1 is not recommended.
For Timer/Counter0, the possible prescaled selections are: clk
clk
Setting the PSR0 bit in SFIOR resets the prescaler. This allows the user to operate with a pre-
dictable prescaler.
• Bit 7 – FOC0: Force Output Compare
The FOC0 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 TCCR0 is written when
operating in PWM mode. When writing a logical one to the FOC0 bit, an immediate compare
match is forced on the waveform generation unit. The OC0 output is changed according to its
Bit
Read/Write
Initial Value
T0S
TOSC1
/128, clk
clk
PSR0
CS00
CS01
CS02
AS0
I/O
T0S
FOC0
I/O
/256, and clk
W
7
0
. By setting the AS0 bit in ASSR, Timer/Counter0 is asynchronously clocked
WGM00
R/W
6
0
clk
T0S
T0S
/1024. Additionally, clk
COM01
R/W
5
0
Clear
COM00
R/W
TIMER/COUNTER0 CLOCK SOURCE
4
0
0
T0
WGM01
R/W
. clk
3
0
10-BIT T/C PRESCALER
T0S
T0
clk
as well as 0 (stop) may be selected.
T0
is by default connected to the main
CS02
R/W
2
0
T0S
CS01
ATmega128A
R/W
/8, clk
1
0
T0S
CS00
R/W
/32, clk
0
0
TCCR0
T0S
/64,
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