ATMEGA644PV ATMEL [ATMEL Corporation], ATMEGA644PV Datasheet - Page 35

• Manufacturer Part Number: ATMEGA644PV
• Description: 8-bit Microcontroller with 16/32/64K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

8011D–AVR–02/07
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
31.
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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