ATMEGA329P-20MN Atmel, ATMEGA329P-20MN Datasheet - Page 30

• Manufacturer Part Number: ATMEGA329P-20MN
• Description: IC MCU AVR 32K 20MHZ 64QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA329P-20MN

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K 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: 64-MLF®, 64-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.5
8021G–AVR–03/11
Low-frequency Crystal Oscillator
Table 8-4.
Notes:
The Low-frequency Crystal Oscillator is optimized for use with a 32.768kHz watch crystal. When
selecting crystals, load capacitance and crystal’s Equivalent Series Resistance, ESR must be
taken into consideration. Both values are specified by the crystal vendor.
ATmega329P/3290P oscillator is optimized for very low power consumption, and thus when
selecting crystals, see
12.5pF crystals.
Table 8-5.
Note:
The Low-frequency Crystal Oscillator provides an internal load capacitance,
page 30
Table 8-6.
CKSEL0
ATmega329P/3290P
0
1
1
1
1
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
1. Maximum ESR is typical value based on characterization
at each TOSC pin.
Device
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.
SUT1..0
Start-up Times for the Crystal Oscillator Clock Selection (Continued)
Maximum ESR Recommendation for 32.768kHz Watch Crystal
ATmega329P/3290P
Capacitance for Low-frequency Oscillator
11
00
01
10
11
Crystal CL (pF)
12.5
6.5
9.0
Table 8-5
Start-up Time from
Power-down and
Power-save
32kHz Osc. Type
1K CK
1K CK
16K CK
16K CK
16K CK
System Osc.
Timer Osc.
for maximum ESR recommendations on 6.5pF, 9.0pF and
(2)
(2)
Additional Delay
14CK + 4.1ms
14CK + 4.1ms
14CK + 65ms
14CK + 65ms
Cap(Xtal1/Tosc1)
(V
from Reset
CC
14CK
ATmega329P/3290P
= 5.0V)
16pF
16pF
Max ESR [kΩ]
75
65
30
Ceramic resonator, fast
rising power
Ceramic resonator,
slowly rising power
Crystal Oscillator, BOD
enabled
Crystal Oscillator, fast
rising power
Crystal Oscillator,
slowly rising power
Recommended Usage
Cap(Xtal2/Tosc2)
(1)
seeTable 8-6 on
6pF
6pF
30