Datasheet

45
ATmega8515(L)
2512G–AVR–03/05
Figure 22. Reset Logic
Notes: 1. The Power-on Reset will not work unless the supply voltage has been below V
POT
(falling).
2. V
BOT
may be below nominal minimum operating voltage for some devices. For
devices where this is the case, the device is tested down to V
CC
= V
BOT
during the
production test. This guarantees that a Brown-out Reset will occur before V
CC
drops
to a voltage where correct operation of the microcontroller is no longer guaranteed.
The test is performed using BODLEVEL=1 for ATmega8515L and BODLEVEL=0 for
ATmega8515. BODLEVEL=1 is not applicable for ATmega8515.
Table 18. Reset Characteristics
Symbol Parameter Condition Min Typ Max Units
V
POT
Power-on Reset Threshold
Voltage (rising)
(1)
1.4 2.3 V
Power-on Reset Threshold
Voltage (falling)
1.3 2.3 V
V
RST
RESET Pin Threshold Voltage 0.1 0.9 V
CC
t
RST
Minimum pulse width on
RESET
Pin
1.5 µs
V
BOT
Brown-out Reset Threshold
Voltage
(2)
BODLEVEL = 1 2.5 2.7 3.2
V
BODLEVEL = 0 3.7 4.0 4.2
t
BOD
Minimum low voltage period for
Brown-out Detection
BODLEVEL = 1 2 µs
BODLEVEL = 0 2 µs
V
HYST
Brown-out Detector hysteresis 130 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
Watchdog
Oscillator
SUT[1:0]
Power-on
Reset Circuit
Reset Circuit
Watchdog
Timer