Datasheet

281
ATmega32A [DATASHEET]
Atmel-8155D-AVR-ATmega32A-Datasheet_02/2014
Notes: 1. R should be in the range 3 k - 100 k, and C should be at least 20 pF. The C values given in the table includes pin
capacitance. This will vary with package type.
2. The frequency will vary with package type and board layout.
28.5 System and Reset Characteristics
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 and BODLEVEL = 0 for ATmega32A.
28.6 Two-wire Serial Interface Characteristics
Table 27-2 describes the requirements for devices connected to the Two-wire Serial Bus. The ATmega32A Two-wire Serial
Interface meets or exceeds these requirements under the noted conditions.
Figure 28-4. External RC Oscillator, Typical Frequencies (V
CC
= 5V)
R [k]
(1)
C [pF] f
(2)
33 22 650kHz
10 22 2.0MHz
Table 28-1. Reset, Brown-out and Internal Voltage Reference 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)
1.3 2.3 V
V
RST
RESET Pin Threshold
Voltage
0.2 V
CC
0.9 V
CC
V
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 2.9
V
BODLEVEL = 0 3.6 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
50 mV
V
BG
Bandgap reference voltage 1.15 1.23 1.35 V
t
BG
Bandgap reference start-up
time
40 70 µs
I
BG
Bandgap reference current
consumption
10 µA