ATMEGA6490A-AU Atmel, ATMEGA6490A-AU Datasheet - Page 50

• Manufacturer Part Number: ATMEGA6490A-AU
• Description: IC MCU AVR 64K FLASH 100TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA6490A-AU

• 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: 69
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K 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: 100-TFQFP
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 69
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10.2.3
10.2.4
8284A–AVR–10/10
Brown-out Detection
Watchdog Reset
ATmega169A/169PA/329A/329PA/3290A/3290PA/649A/649P/6490A/6490P has an On-chip
Brown-out Detection (BOD) circuit for monitoring the V
to a fixed trigger level. The trigger level for the BOD can be selected by the BODLEVEL Fuses.
The trigger level has a hysteresis to ensure spike free Brown-out Detection. The hysteresis on
the detection level should be interpreted as V
V
in
trigger level (V
t
The BOD circuit will only detect a drop in V
ger than t
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
”Watchdog Timer” on page 51
Figure 10-6. Watchdog Reset During Operation
TOUT
HYST
ATmega169A/169PA/329A/329PA/649A/649P/3290A/3290PA/6490A/6490P
Figure
has expired.
/2.When the BOD is enabled, and V
BOD
10-5), the Brown-out Reset is immediately activated. When V
CC
given in
BOT+
INTERNAL
TIME-OUT
RESET
RESET
in
V
CC
”System and Reset Characteristics” on page
Figure
10-5), the delay counter starts the MCU after the Time-out period
for details on operation of the Watchdog Timer.
V
CK
BOT-
CC
CC
decreases to a value below the trigger level (V
if the voltage stays below the trigger level for lon-
BOT+
CC
= V
level during operation by comparing it
BOT
V
t
TOUT
BOT+
+ V
354.
HYST
CC
/2 and V
increases above the
BOT-
TOUT
. Refer to
= V
BOT
BOT-
50
-