ATMEGA325P-20MU Atmel, ATMEGA325P-20MU Datasheet - Page 47

• Manufacturer Part Number: ATMEGA325P-20MU
• Description: IC MCU AVR 32K FLASH 64-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA325P-20MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K 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-MLF®, 64-QFN
• Processor Series: ATMEGA32x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: SPI, UART, USI
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 3
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• For Use With: ATSTK600-TQFP64 - STK600 SOCKET/ADAPTER 64-TQFP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRISP2 - PROGRAMMER AVR IN SYSTEM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATMEGA325P-16MU; ATMEGA325P-16MU

10.2.2
10.2.3
8023F–AVR–07/09
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
ATmega325P/3250P has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
level during 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
value below the trigger level (V
vated. When V
starts the MCU after the Time-out period t
The BOD circuit will only detect a drop in V
ger than t
BOT
INTERNAL
TIME-OUT
+ V
RESET
RESET
HYST
BOD
V
CC
CC
/2 and V
given in
CC
increases above the trigger level (V
BOT-
”System and Reset Characterizations” on page
= V
”System and Reset Characterizations” on page
V
POT
BOT
BOT-
- V
HYST
in
Figure
/2.When the BOD is enabled, and V
TOUT
CC
if the voltage stays below the trigger level for lon-
has expired.
10-5), the Brown-out Reset is immediately acti-
V
RST
t
TOUT
BOT+
ATmega325P/3250P
TOUT
in
– has expired.
Figure
RST
308.
– on its positive edge, the
10-5), the delay counter
308) will generate a
CC
decreases to a
BOT+
47
CC
=