ATMEGA8-16PI Atmel, ATMEGA8-16PI Datasheet - Page 40

• Manufacturer Part Number: ATMEGA8-16PI
• Description: IC AVR MCU 8K 16MHZ IND 28-DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8-16PI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• 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): 4.5 V ~ 5.5 V
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: ATMEGA816PI

External Reset
Brown-out Detection
40
ATmega8(L)
An External Reset is generated by a low level on the RESET pin. Reset pulses longer than the
minimum pulse width (see
running. Shorter pulses are not guaranteed to generate a reset. When the applied signal
reaches the Reset Threshold Voltage – V
MCU after the time-out period t
Figure 17. External Reset During Operation
ATmega8 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
operation by comparing it to a fixed trigger level. The trigger level for the BOD can be selected
by the fuse BODLEVEL to be 2.7V (BODLEVEL unprogrammed), or 4.0V (BODLEVEL pro-
grammed). The trigger level has a hysteresis to ensure spike free Brown-out Detection. The
hysteresis on the detection level should be interpreted as
V
The BOD circuit can be enabled/disabled by the fuse BODEN. When the BOD is enabled
(BODEN programmed), and V
18), the Brown-out Reset is immediately activated. When V
(V
expired.
The BOD circuit will only detect a drop in V
ger than t
Figure 18. Brown-out Reset During Operation
BOT+
BOT+
= V
in
BOD
BOT
Figure
CC
+ V
given in
INTERNAL
TIME-OUT
HYST
18), the delay counter starts the MCU after the time-out period t
RESET
RESET
V
CC
/2 and V
Table 15 on page
Table 15 on page
BOT-
CC
TOUT
decreases to a value below the trigger level (V
= V
has expired.
BOT
V
BOT-
38.
- V
RST
CC
HYST
if the voltage stays below the trigger level for lon-
38) will generate a reset, even if the clock is not
on its positive edge, the delay counter starts the
/2.
CC
V
t
TOUT
BOT+
increases above the trigger level
CC
BOT-
2486Z–AVR–02/11
level during
TOUT
in
Figure
has