ATMEGA328P-AU Atmel, ATMEGA328P-AU Datasheet - Page 33

• Manufacturer Part Number: ATMEGA328P-AU
• Description: MCU AVR 32K FLASH 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA328P-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• 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): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TQFP, 32-VQFP
• Processor Series: ATMEGA32x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: 2-Wire, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 23
• Number Of Timers: 3
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 20MHz
• Total Internal Ram Size: 2KB
• # I/os (max): 23
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 2.5/3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 1.8V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 32
• Package Type: TQFP
• Controller Family/series: AVR MEGA
• No. Of I/o's: 23
• Eeprom Memory Size: 1KB
• Ram Memory Size: 2KB
• Cpu Speed: 20MHz
• Rohs Compliant: Yes
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVR
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATMEGA328P-20AU; ATMEGA328P-20AU; Q3790246

9.5
8271D–AVR–05/11
Low Frequency Crystal Oscillator
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
t a k e n i n t o c o n s i d e r a t i o n . B o t h v a l u e s a r e s p e c i f i e d b y t h e c r y s t a l v e n d o r .
ATmega48A/PA/88A/PA/168A/PA/328/P oscillator is optimized for very low power consumption,
and thus when selecting crystals, see
9.0pF and 12.5pF crystals
Table 9-7.
Note:
The Low-frequency Crystal Oscillator provides an internal load capacitance, see
each TOSC pin.
Table 9-8.
The capacitance (Ce+Ci) needed at each TOSC pin can be calculated by using:
where:
Crystals specifying load capacitance (CL) higher than 6 pF, require external capacitors applied
as described in
The Low-frequency Crystal Oscillator must be selected by setting the CKSEL Fuses to “0110” or
“0111”, as shown in
shown in
Table 9-9.
C
ATmega48A/PA/88A/PA/168A/PA/3
=
SUT1...0
– Ce - is optional external capacitors as described in
– Ci - is the pin capacitance in
– CL - is the load capacitance for a 32.768kHz crystal specified by the crystal vendor
– CS - is the total stray capacitance for one TOSC pin.
2 CL
00
01
10
11
⋅
1. Maximum ESR is typical value based on characterization
Table
–
C
s
Device
Maximum ESR Recommendation for 32.768kHz Crystal
Capacitance for Low-frequency Oscillator
Start-up Times for the Low-frequency Crystal Oscillator Clock Selection
28/P
Additional Delay from Reset (V
Figure 9-2 on page
9-9.
Crystal CL (pF)
Table 9-10 on page
ATmega48A/PA/88A/PA/168A/PA/328/P
12.5
6.5
9.0
4 CK + 4.1ms
4 CK + 65ms
4 CK
Table 9-8
30.
32kHz Osc. Type
System Osc.
Table
Timer Osc.
34. Start-up times are determined by the SUT Fuses as
CC
for maximum ESR recommendations on 6.5pF,
= 5.0V)
Reserved
Recommended Usage
Fast rising power or BOD enabled
Slowly rising power
Stable frequency at start-up
Cap(Xtal1/Tosc1)
Figure 9-2 on page 30
18pF
18pF
Max ESR [kΩ]
75
65
30
Cap(Xtal2/Tosc2)
(1)
Table 9-8
8pF
8pF
33
at