ATMEGA644PV ATMEL [ATMEL Corporation], ATMEGA644PV Datasheet - Page 51

• Manufacturer Part Number: ATMEGA644PV
• Description: 8-bit Microcontroller with 16/32/64K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

9.0.3
8011D–AVR–02/07
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
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
CC
is below the detection level. The POR circuit can be used to trigger the start-up Reset, as
BODLEVEL [2..0]
CC
decreases below the detection level.
”System and Reset Characteristics” on page
Reset Logic
Pull-up Resistor
JTAG Reset
Register
FILTER
SPIKE
CC
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
ATmega164P/324P/644P
Register (MCUSR)
MCU Status
DATA BUS
Delay Counters
329. The POR is activated whenever
TIMEOUT
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