ATMEGA168-20PU Atmel, ATMEGA168-20PU Datasheet - Page 31

• Manufacturer Part Number: ATMEGA168-20PU
• Description: IC AVR MCU 16K 20MHZ 28DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA168-20PU

• 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: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Processor Series: ATMEGA16x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 1 KB
• Interface Type: 2-Wire, SPI, USART, Serial
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 23
• Number Of Timers: 3
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 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, 6 Channel
• A/d Inputs: 6-Channel, 10-Bit
• Cpu Speed: 20 MIPS
• Eeprom Memory: 512 Bytes
• Input Output: 23
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin PDIP
• Programmable Memory: 16K Bytes
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 4.5-5.5 V
• Controller Family/series: AVR MEGA
• No. Of I/o's: 23
• Eeprom Memory Size: 512Byte
• Ram Memory Size: 1KB
• Rohs Compliant: Yes
• For Use With: ATSTK600-TQFP32 - STK600 SOCKET/ADAPTER 32-TQFPATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATAVRISP2 - PROGRAMMER AVR IN SYSTEMATJTAGICE2 - AVR ON-CHIP D-BUG SYSTEM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.5
6.6
2545E–AVR–02/05
Low Frequency Crystal Oscillator
Calibrated Internal RC Oscillator
The device can utilize a 32.768 kHz watch crystal as clock source by a dedicated Low Fre-
quency Crystal Oscillator. The crystal should be connected as shown in
Oscillator is selected, start-up times are determined by the SUT Fuses and CKSEL0 as shown in
Table
Table 6-7.
Note:
The calibrated internal RC Oscillator by default provides a 8.0 MHz clock. The frequency is nom-
inal value at 3V and 25°C. The device is shipped with the CKDIV8 Fuse programmed. See
”System Clock Prescaler” on page 34
clock by programming the CKSEL Fuses as shown in
no external components. During reset, hardware loads the calibration byte into the OSCCAL
Register and thereby automatically calibrates the RC Oscillator. At 3V and 25°C, this calibration
gives a frequency of 8 MHz ±10%. The oscillator can be calibrated to any frequency in the range
7.3 - 8.1 MHz within ±2% accuracy, by changing the OSCCAL register. When this Oscillator is
used as the chip clock, the Watchdog Oscillator will still be used for the Watchdog Timer and for
the Reset Time-out. For more information on the pre-programmed calibration value, see the sec-
tion
Table 6-8.
Notes:
Power Conditions
BOD enabled
Fast rising power
Slowly rising power
BOD enabled
Fast rising power
Slowly rising power
”Calibration Byte” on page
6-7.
1. These options should only be used if frequency stability at start-up is not important for the
1. The device is shipped with this option selected.
2. The frequency ranges are preliminary values. Actual values are TBD.
3. If 8 MHz frequency exceeds the specification of the device (depends on V
application.
Frequency Range
Fuse can be programmed in order to divide the internal frequency by 8.
Start-up Times for the Low Frequency Crystal Oscillator Clock Selection
Internal Calibrated RC Oscillator Operating Modes
7.3 - 8.1
(2)
Start-up Time from
Power-down and
(MHz)
284.
Reserved
Reserved
Power-save
32K CK
32K CK
32K CK
1K CK
1K CK
1K CK
for more details. This clock may be selected as the system
Additional Delay
14CK + 4.1 ms
14CK + 65 ms
14CK + 4.1 ms
Table
14CK + 65 ms
(V
from Reset
CC
14CK
14CK
= 5.0V)
6-8. If selected, it will operate with
ATmega48/88/168
(1)
(1)(3)
CKSEL3..0
(1)
(1)
0010
Figure
CKSEL0
CC
1
0
0
0
0
1
1
1
), the CKDIV8
6-2. When this
SUT1..0
00
01
10
11
00
01
10
11
31