ATMEGA644P-15AT Atmel, ATMEGA644P-15AT Datasheet - Page 35

• Manufacturer Part Number: ATMEGA644P-15AT
• Description: MCU AVR 64K FLASH 15MHZ 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644P-15AT

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• 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): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

7674F–AVR–09/09
Figure 7-3.
Table 7-8.
Crystals specifying load capacitance (CL) higher than 8.0 pF, require external capacitors applied
as described in
To find suitable load capacitance for a 32.768 kHz crysal, please consult the crystal datasheet.
When this oscillator is selected, start-up times are determined by the SUT Fuses and CKSEL0
as shown in
Table 7-9.
Note:
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
BOD enabled
Fast rising power
Slowly rising power
1. These options should only be used if frequency stability at start-up is not important for the
application.
Min. (pF)
Table
TBD
Crystal Oscillator Connections
Low-frequency Crystal Oscillator Internal load Capacitance
Start-up Times for the Low Frequency Crystal Oscillator Clock Selection
Figure 7-2 on page
7-9.
Start-up Time from
Power-down and
Reserved
Reserved
Power-save
32K CK
32K CK
32K CK
1K CK
1K CK
1K CK
32.
Typ. (pF)
8.0
ATmega164P/324P/644P
TOSC2
TOSC1
Additional Delay
14CK + 4.1 ms
14CK + 65 ms
14CK + 4.1 ms
14CK + 65 ms
(V
from Reset
CC
14CK
14CK
= 5.0V)
(1)
(1)
(1)
CKSEL0
Max. (pF)
TBD
0
0
0
0
1
1
1
1
SUT1..0
00
01
10
11
00
01
10
11
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