ATMEGA1281-16MU Atmel, ATMEGA1281-16MU Datasheet - Page 43

• Manufacturer Part Number: ATMEGA1281-16MU
• Description: IC MCU AVR 128K FLASH 64-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA1281-16MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-MLF®, 64-QFN
• Processor Series: ATMEGA128x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 8 KB
• Interface Type: 2-Wire, SPI, UART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 6
• Operating Supply Voltage: 4.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, ATAVRRZ541, ATAVRRAVEN, ATAVRRZRAVEN, ATAVRRZUSBSTICK, ATAVRISP2, ATAVRRZ201
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 channel
• For Use With: ATSTK600-TQFP64 - STK600 SOCKET/ADAPTER 64-TQFPATAVRDB101 - MODULE DISPLAY LCD/RGB BACKLIGHT770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRISP2 - PROGRAMMER AVR IN SYSTEMATJTAGICE2 - AVR ON-CHIP D-BUG SYSTEM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2549M–AVR–09/10
C1 and C2 should always be equal for both crystals and resonators. The optimal value of the
capacitors depends on the crystal or resonator in use, the amount of stray capacitance, and the
electromagnetic noise of the environment. Some initial guidelines for choosing capacitors for
use with crystals are given in
the manufacturer should be used.
Figure 9-2.
The Low Power Oscillator can operate in three different modes, each optimized for a specific fre-
quency range. The operating mode is selected by the fuses CKSEL3:1 as shown in
Table 9-3.
Notes:
The CKSEL0 Fuse together with the SUT1:0 Fuses select the start-up times as shown in
9-4.
Table 9-4.
Ceramic resonator, slowly
Ceramic resonator, BOD
Ceramic resonator, fast
Oscillator Source /
Power Conditions
Frequency Range (MHz)
rising power
rising power
1. This is the recommended CKSEL settings for the different frequency ranges.
2. This option should not be used with crystals, only with ceramic resonators.
3. If 8 MHz frequency exceeds the specification of the device (depends on V
4. Max frequency when using ceramic oscillator is 10 MHz.
enabled
Fuse can be programmed in order to divide the internal frequency by 8. It must be ensured
that the resulting divided clock meets the frequency specification of the device.
8.0 - 16.0
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
Crystal Oscillator Connections
Low Power Crystal Oscillator Operating Modes
Start-up Times for the Low Power Crystal Oscillator Clock Selection
(4)
Start-up Time from
Table
Power-down and
ATmega640/1280/1281/2560/2561
Power-save
258 CK
258 CK
1K CK
9-3. For ceramic resonators, the capacitor values given by
C2
C1
CKSEL3:1
100
101
110
111
(2)
(1)
Additional Delay
14CK + 4.1 ms
14CK + 65 ms
Recommended Range for Capacitors C1
(V
from Reset
XTAL2
XTAL1
GND
CC
14CK
= 5.0V)
(3)
(2)
(1)
(1)
and C2 (pF)
12 - 22
12 - 22
12 - 22
–
CKSEL0
CC
0
0
0
), the CKDIV8
Table
SUT1:0
00
01
10
9-3.
Table
43