ATmega1281R231 Atmel Corporation, ATmega1281R231 Datasheet - Page 61

• Manufacturer Part Number: ATmega1281R231
• Manufacturer: Atmel Corporation

Specifications of ATmega1281R231

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 16 MHz
• Max I/o Pins: 54
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Crypto Engine: AES
• Sram (kbytes): 8
• Eeprom (bytes): 4096
• Operating Voltage (vcc): 1.8 to 3.6
• Timers: 6
• Frequency Band: 2.4 GHz
• Max Data Rate (mb/s): 2
• Antenna Diversity: Yes
• External Pa Control: Yes
• Power Output (dbm): 3
• Receiver Sensitivity (dbm): -101
• Receive Current Consumption (ma): 13.2
• Transmit Current Consumption (ma): 14.4
• Link Budget (dbm): 104

12.2.2
12.2.3
2549N–AVR–05/11
External Reset
Brown-out Detection
Figure 12-3. 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 12-4. 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
12-5 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 12-5 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