51
2467S–AVR–07/09
ATmega128
Figure 22.
Reset Logic
Notes:
1. The Power-on Reset will not work unless the supply voltage has been below V
POT
(falling)
Table 19.
Reset Characteristics
Symbol
Parameter
Condition
Min
Typ
Max
Units
V
POT
Power-on Reset
Threshold Voltage
(rising)
1.4
2.3
V
Power-on Reset
Threshold Voltage
(falling)
1.3
2.3
V
V
RST
RESET Pin Threshold
Voltage
0.2 V
CC
0.85 V
CC
V
t
RST
Pulse width on RESET
Pin
1.5
µs
V
BOT
Brown-out Reset
Threshold Voltage
BODLEVEL = 1
2.4
2.6
2.9
V
BODLEVEL = 0
3.7
4.0
4.5
t
BOD
Minimum low voltage
period for Brown-out
Detection
BODLEVEL = 1
2
µs
BODLEVEL = 0
2
V
HYST
Brown-out Detector
hysteresis
100
mV
MCU Control and Status
Register (MCUCSR)
Brown-Out
Reset Circuit
BODEN
BODLEVEL
Delay Counters
CKSEL[3:0]
CK
TIMEOUT
WDRF
BORF
EXTRF
PORF
DATA BUS
Clock
Generator
SPIKE
FILTER
Pull-up Resistor
JTRF
JTAG Reset
Register
Watchdog
Oscillator
SUT[1:0]
COUNTER RESET
Watchdog
Timer
RESET
Pull-up Resistor
PEN
Reset Circuit
L
D
Q
Q
Power-On Reset
Circuit