ATMEGA48V_11 ATMEL [ATMEL Corporation], ATMEGA48V_11 Datasheet - Page 30

• Manufacturer Part Number: ATMEGA48V_11
• Description: 8-bit Atmel Microcontroller with 4/8/16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

2545T–AVR–05/11
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.
Oscillator source/
power conditions
Ceramic resonator,
fast rising power
Ceramic resonator,
slowly rising power
Ceramic resonator,
BOD enabled
Ceramic resonator,
fast rising power
Ceramic resonator,
slowly rising power
Frequency range
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 8MHz frequency exceeds the specification of the device (depends on V
8.0 - 16.0
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
(MHz)
Fuse can be programmed in order to divide the internal frequency by eight. It must be ensured
that the resulting divided clock meets the frequency specification of the device.
Crystal oscillator connections.
Low power crystal oscillator operating modes
Start-up times for the low power crystal oscillator clock selection.
Start-up time from
power-down and
power-save
258CK
258CK
1KCK
1KCK
1KCK
C2
capacitors C1 and C2 (pF)
C1
Recommended range for
12 - 22
12 - 22
12 - 22
–
Additional delay
14CK + 4.1ms
14CK + 4.1ms
14CK + 65ms
14CK + 65ms
(V
from reset
XTAL2
XTAL1
GND
CC
14CK
(3)
= 5.0V)
.
ATmega48/88/168
(2)
(1)
(2)
(1)
(2)
CKSEL0
CC
0
0
0
0
1
CKSEL3..1
), the CKDIV8
100
101
110
111
Table
(2)
SUT1..0
(1)
00
01
10
11
00
Table
9-3.
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