ATMEGA649A-AU Atmel, ATMEGA649A-AU Datasheet - Page 34

• Manufacturer Part Number: ATMEGA649A-AU
• Description: IC MCU AVR 64K FLASH 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA649A-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.6
8284A–AVR–10/10
Low-frequency Crystal Oscillator
Table 8-6.
Notes:
The Low-frequency Crystal Oscillator is optimized for use with a 32.768 kHz watch crystal.
When selecting crystals, load capacitance and crystal’s Equivalent Series Resistance, ESR
must be taken into consideration. Both values are specified by the crystal vendor.
ATmega329A/329PA oscillator is optimized for very low power consumption, and thus when
selecting crystals, see
crystals
Table 8-7.
Note:
The Low-frequency Crystal Oscillator provides an internal load capacitance, see
page 35
ATmega169A/169PA/329A/329PA/649A/649P/3290A/3290PA/6490A/6490P oscillator is opti-
mized for very low power consumption, and thus when selecting crystals, see
34
Table 8-8.
Note:
CKSEL0
ATmega169A/169PA/329A/329PA/649A/649P/3290A/3290PA/6490A/6490P
for maximum ESR recommendations on 6.5 pF, 9.0 pF and 12.5 pF crystals.
1
1
1
1. These options should only be used when not operating close to the maximum frequency of the
2. These options are intended for use with ceramic resonators and will ensure frequency stability
1. Maximum ESR is typical value based on characterization
1. Maximum ESR is typical value based on characterization
at each TOSC pin.
device, and only if frequency stability at start-up is not important for the application. These
options are not suitable for crystals.
at start-up. They can also be used with crystals when not operating close to the maximum fre-
quency of the device, and if frequency stability at start-up is not important for the application.
SUT1..0
Start-up Times for the Crystal Oscillator Clock Selection (Continued)
Maximum ESR Recommendation for 32.768 kHz Watch Crystal
ATmega169A/169PA
Maximum ESR Recommendation for 32.768 kHz Watch Crystal
ATmega329A/329PA/3290A/3290PA/649A/649P/6490A/6490P
01
10
11
Crystal CL (pF)
Crystal CL (pF)
12.5
6.5
9.0
6.5
9
Table 8-7
Start-up Time from
Power-down and
Power-save
16K CK
16K CK
16K CK
for maximum ESR recommendations on 9 pF and 6.5 pF
Additional Delay
14CK + 4.1 ms
14CK + 65 ms
(V
from Reset
CC
14CK
= 5.0V)
Max ESR [kΩ]
Max ESR [kΩ]
75
65
30
60
35
Crystal Oscillator, BOD
enabled
Crystal Oscillator, fast
rising power
Crystal Oscillator,
slowly rising power
Recommended Usage
Table 8-8 on page
(1)
(1)
Table 8-9 on
34