ATmega1281 Atmel Corporation, ATmega1281 Datasheet - Page 371

• Manufacturer Part Number: ATmega1281
• Manufacturer: Atmel Corporation

Specifications of ATmega1281

• 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: 54
• Ext Interrupts: 17
• Usb Speed: No
• Usb Interface: No
• Spi: 3
• 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): 8
• 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: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 16
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

31.3
31.3.1
Table 31-1.
Notes:
31.3.2
31.4
2549N–AVR–05/11
Factory Calibration
User Calibration
Clock Characteristics
1. Voltage range for ATmega640V/1281V/1280V/2561V/2560V.
2. Voltage range for ATmega640/1281/1280/2561/2560.
External Clock Drive
Calibrated Internal RC Oscillator Accuracy
External Clock Drive Waveforms
Calibration Accuracy of Internal RC Oscillator
Figure 31-5. External Clock Drive Waveforms
Table 31-2.
Symbol
7.3MHz - 8.1MHz
1/t
Δ
t
t
t
t
t
CHCX
CLCX
CLCH
CHCL
CLCL
t
CLCL
CLCL
Frequency
8.0MHz
Parameter
Oscillator
Frequency
Clock Period
High Time
Low Time
Rise Time
Fall Time
Change in period
from one clock
cycle to the next
External Clock Drive
V
IL1
V
IH1
1.8V - 5.5V
2.7V - 5.5V
ATmega640/1280/1281/2560/2561
V
V
3V
Min.
CC
500
200
200
CC
0
= 1.8V - 5.5V
(1)
(2)
Max.
2.0
2.0
2
2
V
Min.
CC
125
Temperature
50
50
-40°C - 85°C
0
= 2.7V - 5.5V
25°C
Max.
1.6
1.6
8
2
V
Min.
62.5
CC
25
25
0
Calibration Accuracy
= 4.5V - 5.5V
Max.
±10%
0.5
0.5
±1%
16
2
Units
MHz
ns
μs
%
371