ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 41

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

9.3
7701E–AVR–02/11
Power-on Reset
Figure 9-1.
A Power-on Reset (POR) pulse is generated by an On-chip detection circuit. The detection
level is defined in
whenever V
Reset, as well as to detect a failure in supply voltage.
A 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
decreases below the detection level.
Figure 9-2.
INTERNAL
V
TIME-OUT
BODLEVEL [1..0]
CC
RESET
RESET
V
CC
CCRR
Reset Logic
MCU Start-up, RESET Tied to V
is below the detection level. The POR circuit can be used to trigger the Start-up
CC
“System and Reset Characterizations” on page
Pull-up Resistor
rise. The RESET signal is activated again, without any delay, when V
FILTER
SPIKE
V
V
V
RST
PORMA X
PORMIN
Atmel ATtiny24/44/84 [Preliminary]
t
TOUT
CKSEL[1:0]
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
181. The POR is activated
TIMEOUT
41
CC