ATMEGA48V_09 ATMEL [ATMEL Corporation], ATMEGA48V_09 Datasheet - Page 45

• Manufacturer Part Number: ATMEGA48V_09
• Description: 8-bit Microcontroller with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

10.3
2545R–AVR–07/09
Power-on Reset
Figure 10-1. Reset Logic
A Power-on Reset (POR) pulse is generated by an On-chip detection circuit. The detection level
is defined in
V
well as to detect a failure in supply voltage.
A Power-on Reset (POR) circuit ensures that the device is reset from Power-on. Reaching the
Power-on Reset threshold voltage invokes the delay counter, which determines how long the
device is kept in RESET after V
when V
Figure 10-2. MCU Start-up, RESET Tied to V
CC
is below the detection level. The POR circuit can be used to trigger the start-up Reset, as
INTERNAL
TIME-OUT
BODLEVEL [2..0]
RSTDISBL
CC
RESET
RESET
V
decreases below the detection level.
CC
“System and Reset Characteristics” on page
Pull-up Resistor
FILTER
SPIKE
V
V
POT
RST
CC
t
TOUT
CKSEL[3:0]
rise. The RESET signal is activated again, without any delay,
Power-on Reset
Reset Circuit
SUT[1:0]
Brown-out
Watchdog
Oscillator
Generator
Circuit
Clock
CK
CC
Register (MCUSR)
MCU Status
DATA BUS
Delay Counters
306. The POR is activated whenever
ATmega48/88/168
TIMEOUT
45