ATMEGA328P-20PU Atmel, ATMEGA328P-20PU Datasheet - Page 30

• 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

8.4
8025K–AVR–10/09
Full Swing Crystal Oscillator
Table 8-4.
Notes:
Pins XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can be
configured for use as an On-chip Oscillator, as shown in
crystal or a ceramic resonator may be used.
This Crystal Oscillator is a full swing oscillator, with rail-to-rail swing on the XTAL2 output. This is
useful for driving other clock inputs and in noisy environments. The current consumption is
higher than the
Oscillator will only operate for V
C1 and C2 should always be equal for both crystals and resonators. The optimal value of the
capacitors depends on the crystal or resonator in use, the amount of stray capacitance, and the
electromagnetic noise of the environment. Some initial guidelines for choosing capacitors for
use with crystals are given in
ues given by the manufacturer should be used.
The operating mode is selected by the fuses CKSEL3..1 as shown in
Table 8-5.
Note:
Oscillator Source /
Power Conditions
Crystal Oscillator, BOD
enabled
Crystal Oscillator, fast
rising power
Crystal Oscillator, slowly
rising power
Frequency Range (MHz)
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
If 8 MHz frequency exceeds the specification of the device (depends on V
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.
0.4 - 20
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.
Start-up Times for the Low Power Crystal Oscillator Clock Selection (Continued)
Full Swing Crystal Oscillator operating modes
”Low Power Crystal Oscillator” on page
Start-up Time from
Table 8-6 on page
Power-down and
CC
Power-save
= 2.7 - 5.5 volts.
16K CK
16K CK
16K CK
Capacitors C1 and C2 (pF)
Recommended Range for
12 - 22
31. For ceramic resonators, the capacitor val-
ATmega48P/88P/168P
Additional Delay
14CK + 4.1 ms
14CK + 65 ms
(V
from Reset
Figure 8-2 on page
CC
28. Note that the Full Swing Crystal
14CK
(Note:)
= 5.0V)
Table
CKSEL3..1
CC
CKSEL0
8-5.
), the CKDIV8 Fuse
29. Either a quartz
1
1
1
011
SUT1..0
01
10
11
30