ATMEGA128A-MNR Atmel, ATMEGA128A-MNR Datasheet - Page 53

• Manufacturer Part Number: ATMEGA128A-MNR
• Description: IC MCU AVR 128K FLASH 64VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA128A-MNR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 128KB (64K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP
• Core: AVR8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10.2.2
10.2.3
8151H–AVR–02/11
External Reset
Brown-out Detection
Figure 10-3. 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 10-4. External Reset During Operation
Atmel
V
can be selected by the fuse BODLEVEL to be 2.7V (BODLEVEL unprogrammed), or 4.0V
(BODLEVEL programmed). The trigger level has a hysteresis to ensure spike free Brown-out
Detection. The hysteresis on the detection level should be interpreted as V
and V
The BOD circuit can be enabled/disabled by the fuse BODEN. When the BOD is enabled
(BODEN programmed), and V
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
CC
BOT+
level during operation by comparing it to a fixed trigger level. The trigger level for the BOD
®
BOT-
AVR
in
INTERNAL
TIME-OUT
BOD
Figure
= V
RESET
RESET
®
V
ATmega128A has an On-chip Brown-out Detection (BOD) circuit for monitoring the
CC
given in
BOT
CC
10-5), the delay counter starts the MCU after the time-out period t
- V
HYST
“System and Reset Characteristics” on page
/2.
“System and Reset Characteristics” on page
V
CC
POT
decreases to a value below the trigger level (V
CC
if the voltage stays below the trigger level for lon-
V
RST
t
TOUT
TOUT
CC
has expired.
increases above the trigger level
324.
RST
ATmega128A
on its positive edge, the
BOT+
324) will generate a
BOT-
= V
BOT
in
Figure 10-
+ V
TOUT
HYST
has
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