atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 50

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

8.0.5
50
ATmega32U4
Brown-out Detection
ATmega32U4 has an On-chip Brown-out Detection (BOD) circuit for monitoring the V
during operation by comparing it to a fixed trigger level. The trigger level for the BOD can be
selected by the BODLEVEL Fuses. 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
Table 8-2.
Note:
Table 8-3.
When the BOD is enabled, and V
8-5), the Brown-out Reset is immediately activated. When V
(V
expired.
The BOD circuit will only detect a drop in V
longer than t
Symbol
V
t
BOT
BOD
BOT+
HYST
+ V
BODLEVEL 2..0 Fuses
in
1. V
HYST
Figure
this is the case, the device is tested down to V
antees that a Brown-Out Reset will occur before V
operation of the microcontroller is no longer guaranteed. The test is performed using
BODLEVEL = 110 for ATmega32U4 and BODLEVEL = 101 for ATmega32U4L.
BOD
BOT
/2 and V
Parameter
Brown-out Detector Hysteresis
Min Pulse Width on Brown-out Reset
BODLEVEL Fuse Coding
Brown-out Characteristics
101
100
010
001
000
111
110
011
may be below nominal minimum operating voltage for some devices. For devices where
given in
8-5), the delay counter starts the MCU after the Time-out period t
BOT-
Table
= V
BOT
8-1.
- V
CC
HYST
Min V
decreases to a value below the trigger level (V
(1)
/2.
BOT
CC
if the voltage stays below the trigger level for
Typ V
CC
2.0
2.2
2.4
2.6
3.4
3.5
4.3
BOD Disabled
= V
BOT
CC
Min
BOT
drops to a voltage where correct
CC
during the production test. This guar-
increases above the trigger level
Typ
50
Max V
BOT
Max
Units
Units
mV
ns
V
7766A–AVR–03/08
BOT-
TOUT
in
CC
BOT+
Figure
level
has
=