ATMEGA16-16AU SL602 Atmel, ATMEGA16-16AU SL602 Datasheet - Page 40

• Manufacturer Part Number: ATMEGA16-16AU SL602
• Manufacturer: Atmel

External Reset
Brown-out Detection
2466T–AVR–07/10
An External Reset is generated by a low level on the RESET pin. Reset pulses longer than the
minimum pulse width (see
Shorter pulses are not guaranteed to generate a reset. When the applied signal reaches the
Reset Threshold Voltage – V
the Time-out period t
Figure 18. External Reset During Operation
ATmega16 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
ing operation by comparing it to a fixed trigger level. The trigger level for the BOD can be
selected by the fuse BODLEVEL to be 2.7V (BODLEVEL unprogrammed), or 4.0V (BODLEVEL
programmed). The trigger level has a hysteresis to ensure spike free Brown-out Detection. The
hysteresis on the detection level should be interpreted as V
V
The BOD circuit can be enabled/disabled by the fuse BODEN. When the BOD is enabled
(BODEN programmed), and V
19), the Brown-out Reset is immediately activated. When V
(V
expired.
The BOD circuit will only detect a drop in V
ger than t
Figure 19. Brown-out Reset During Operation
BOT
BOT+
- V
in
HYST
BOD
Figure
/2.
given in
CC
INTERNAL
TIME-OUT
19), the delay counter starts the MCU after the Time-out period t
RESET
RESET
TOUT
V
Table
CC
has expired.
15.
Table
RST
CC
– on its positive edge, the delay counter starts the MCU after
decreases to a value below the trigger level (V
15) will generate a reset, even if the clock is not running.
V
BOT-
CC
if the voltage stays below the trigger level for lon-
CC
V
BOT+
t
TOUT
BOT+
increases above the trigger level
= V
BOT
ATmega16(L)
+ V
HYST
/2 and V
BOT-
CC
level dur-
TOUT
in
Figure
BOT-
has
40
=