ATMEGA168-20AUR Atmel, ATMEGA168-20AUR Datasheet - Page 47

• Manufacturer Part Number: ATMEGA168-20AUR
• Description: MCU AVR 16KB FLASH 20MHZ 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA168-20AUR

• 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 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TQFP, 32-VQFP
• Package: 32TQFP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 23
• Interface Type: SPI/TWI/USART
• On-chip Adc: 8-chx10-bit
• Number Of Timers: 3
• For Use With: ATSTK600-TQFP32 - STK600 SOCKET/ADAPTER 32-TQFPATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVR
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10.6
10.7
10.7.1
2545S–AVR–07/10
Watchdog System Reset
Internal Voltage Reference
Voltage Reference Enable Signals and Start-up Time
Figure 10-5. Brown-out Reset During Operation
When the Watchdog times out, it will generate a short reset pulse of one CK cycle duration. On
the falling edge of this pulse, the delay timer starts counting the Time-out period t
page 48
Figure 10-6. Watchdog System Reset During Operation
ATmega48/88/168 features an internal bandgap reference. This reference is used for Brown-out
Detection, and it can be used as an input to the Analog Comparator or the ADC.
The voltage reference has a start-up time that may influence the way it should be used. The
start-up time is given in
reference is not always turned on. The reference is on during the following situations:
1. When the BOD is enabled (by programming the BODLEVEL [2:0] Fuses).
2. When the bandgap reference is connected to the Analog Comparator (by setting the
3. When the ADC is enabled.
ACBG bit in ACSR).
for details on operation of the Watchdog Timer.
CC
INTERNAL
TIME-OUT
RESET
RESET
V
CC
“System and Reset Characteristics” on page
V
CK
BOT-
V
t
ATmega48/88/168
TOUT
BOT+
306. To save power, the
TOUT
. Refer to
47