ATmega128
Figure 22.
Reset Logic
DATA BUS
PEN
D
L
Q
Q
MCU Control and Status
Register (MCUCSR)
PORF
BORF
EXTRF
WDRF
JTRF
Pull-up Resistor
Power-On Reset
Circuit
BODEN
BODLEVEL
Pull-up Resistor
RESET
SPIKE
FILTER
Brown-Out
Reset Circuit
Reset Circuit
JTAG Reset
Register
Watchdog
Timer
Watchdog
Oscillator
Clock
Generator
CK
Delay Counters
TIMEOUT
CKSEL[3:0]
SUT[1:0]
Table 19.
Reset Characteristics
Symbol
Parameter
Power-on Reset
Threshold Voltage
(rising)
V
POT
Power-on Reset
Threshold Voltage
(falling)
RESET Pin Threshold
Voltage
Pulse width on RESET
Pin
Brown-out Reset
Threshold Voltage
Minimum low voltage
period for Brown-out
Detection
Brown-out Detector
hysteresis
BODLEVEL = 1
BODLEVEL = 0
BODLEVEL = 1
BODLEVEL = 0
0.2 V
CC
1.5
2.4
3.7
2.6
4.0
2
µs
2
100
mV
2.9
V
4.5
Condition
Min
Typ
1.4
Max
2.3
Units
V
1.3
COUNTER RESET
2.3
V
V
RST
t
RST
V
BOT
0.85 V
CC
V
µs
t
BOD
V
HYST
Notes:
1. The Power-on Reset will not work unless the supply voltage has been below V
POT
(falling)
51
2467R–AVR–06/08
ATMEL [ ATMEL CORPORATION ]
