A000047 Arduino, A000047 Datasheet - Page 61

• Manufacturer Part Number: A000047
• Description: MCU, MPU & DSP Development Tools Mega2560
• Manufacturer: Arduino
• Series: -r
• Type: MCUr

Specifications of A000047

• Processor To Be Evaluated: ATmega2560
• Interface Type: USB, I2C, SPI
• Dimensions: 4 in x 2.1 in
• Operating Supply Voltage: 5 V
• Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: ATmega2560

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