ATMEGA328P-20PU Atmel, ATMEGA328P-20PU Datasheet - Page 29

• Manufacturer Part Number: ATMEGA328P-20PU
• Manufacturer: Atmel

Specifications of ATMEGA328P-20PU

• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 20MHz
• Interface Type: SPI/TWI/USART
• Program Memory Type: Flash
• Program Memory Size: 32KB
• Total Internal Ram Size: 2KB
• # I/os (max): 23
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 6-chx10-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Through Hole
• Pin Count: 28
• Package Type: PDIP
• Lead Free Status / Rohs Status: Compliant

8025K–AVR–10/09
Figure 8-2.
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
on page
Table 8-3.
Notes:
The CKSEL0 Fuse together with the SUT1..0 Fuses select the start-up times as shown in
8-4.
Table 8-4.
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 8 MHz frequency exceeds the specification of the device (depends on V
29.
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 8. 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
(1)
Start-up Time from
Power-down and
C2
C1
Power-save
258 CK
258 CK
1K CK
1K CK
1K CK
Capacitors C1 and C2 (pF)
Recommended Range for
12 - 22
12 - 22
12 - 22
–
XTAL2 (TOSC2)
XTAL1 (TOSC1)
GND
ATmega48P/88P/168P
Additional Delay
14CK + 4.1 ms
14CK + 4.1 ms
14CK + 65 ms
14CK + 65 ms
(V
from Reset
CC
14CK
= 5.0V)
(3)
(2)
(1)
(2)
(1)
(2)
CKSEL0
CC
0
0
0
0
1
CKSEL3..1
), the CKDIV8
100
101
110
111
(2)
Table 8-3
SUT1..0
00
01
10
11
00
Table
29