ATMEGA1281V-8MU Atmel, ATMEGA1281V-8MU Datasheet - Page 61

• Manufacturer Part Number: ATMEGA1281V-8MU
• Description: IC MCU AVR 128K FLASH 64-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA1281V-8MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 8K 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: 64-MLF®, 64-QFN
• Processor Series: ATMEGA128x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 8 KB
• Interface Type: 2-Wire, SPI, USART
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 6
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit
• For Use With: ATSTK600-TQFP64 - STK600 SOCKET/ADAPTER 64-TQFPATAVRDB101 - MODULE DISPLAY LCD/RGB BACKLIGHT770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRISP2 - PROGRAMMER AVR IN SYSTEMATJTAGICE2 - AVR ON-CHIP D-BUG SYSTEM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

11.2.2
11.2.3
2549M–AVR–09/10
External Reset
Brown-out Detection
Figure 11-3. MCU Start-up, RESET Extended Externally
An External Reset is generated by a low level on the RESET pin. Reset pulses longer than the
minimum pulse width (see
reset, even if the clock is not running. Shorter pulses are not guaranteed to generate a reset.
When the applied signal reaches the Reset Threshold Voltage – V
delay counter starts the MCU after the Time-out period – t
Figure 11-4. External Reset During Operation
ATmega640/1280/1281/2560/2561 has an On-chip Brown-out Detection (BOD) circuit for moni-
toring the V
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
When the BOD is enabled, and V
11-5 on page
trigger level (V
out period t
The BOD circuit will only detect a drop in V
ger than t
BOT+
INTERNAL
TIME-OUT
= V
RESET
RESET
BOD
BOT
V
CC
TOUT
CC
CC
+ V
given in
62), the Brown-out Reset is immediately activated. When V
BOT+
level during operation by comparing it to a fixed trigger level. The trigger level for
has expired.
HYST
in
/2 and V
Figure 11-5 on page
“System and Reset Characteristics” on page
V
“System and Reset Characteristics” on page
POT
BOT-
ATmega640/1280/1281/2560/2561
CC
= V
decreases to a value below the trigger level (V
BOT
- V
62), the delay counter starts the MCU after the Time-
CC
HYST
if the voltage stays below the trigger level for lon-
V
RST
/2.
t
TOUT
TOUT
– has expired.
RST
372.
– on its positive edge, the
CC
372) will generate a
increases above the
BOT-
in
Figure
61