ATMEGA644V-10MUR Atmel, ATMEGA644V-10MUR Datasheet - Page 47

• Manufacturer Part Number: ATMEGA644V-10MUR
• Description: MCU AVR 64K FLASH 10MHZ 44QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644V-10MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 10MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• 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: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

9.2.2
9.2.3
2593N–AVR–07/10
External Reset
Brown-out Detection
Figure 9-3.
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 9-4.
ATmega644 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
ing operation by comparing it 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
When the BOD is enabled, and V
9-5), the Brown-out Reset is immediately activated. When V
(V
expired.
The BOD circuit will only detect a drop in V
ger than t
BOT
BOT+
INTERNAL
TIME-OUT
+ V
in
RESET
RESET
HYST
BOD
V
Figure
CC
CC
/2 and V
given in
MCU Start-up, RESET Extended Externally
External Reset During Operation
9-5), the delay counter starts the MCU after the Time-out period t
BOT-
”System and Reset Characteristics” on page
= V
V
”System and Reset Characteristics” on page
POT
BOT
- V
CC
HYST
decreases to a value below the trigger level (V
/2.
CC
if the voltage stays below the trigger level for lon-
V
RST
t
TOUT
TOUT
CC
– has expired.
increases above the trigger level
RST
320.
– on its positive edge, the
ATmega644
320) will generate a
BOT-
CC
level dur-
TOUT
in
BOT+
Figure
has
47
=