ATMEGA88P-20MUR Atmel, ATMEGA88P-20MUR Datasheet - Page 49

• Manufacturer Part Number: ATMEGA88P-20MUR
• Description: MCU AVR 8KB FLASH 20MHZ 32QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA88P-20MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K 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: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

10.4
10.5
8025L–AVR–7/10
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
can be disabled by the RSTDISBL fuse, see
Figure 10-4. External Reset During Operation
ATmega48P/88P/168P has an On-chip Brown-out Detection (BOD) circuit for monitoring the
V
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
ately activated. When V
the delay counter starts the MCU after the Time-out period t
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
INTERNAL
TIME-OUT
+ V
RESET
RESET
HYST
BOD
V
CC
CC
/2 and V
given in
BOT-
”System and Reset Characteristics” on page
CC
= V
increases above the trigger level (V
V
”System and Reset Characteristics” on page
POT
BOT
BOT-
- V
in
HYST
Figure 10-5 on page
/2.When the BOD is enabled, and V
CC
Table 27-6 on page
if the voltage stays below the trigger level for lon-
V
RST
t
TOUT
ATmega48P/88P/168P
TOUT
50), the Brown-out Reset is immedi-
TOUT
– has expired. The External Reset
BOT+
has expired.
293.
RST
314.
in
– on its positive edge, the
Figure 10-5 on page
314) will generate a
CC
decreases to a
BOT+
50),
49
=