at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 50

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

8.1.3
50
AT90PWM81
Power-on Reset
Figure 8-1.
Table 8-1.
Notes:
A Power-on Reset (POR) pulse is generated by an On-chip detection circuit. The detection level is defined
in
used to trigger the start-up Reset, as well as to detect a failure in supply voltage.
A Power-on Reset (POR) circuit ensures that the device is reset from Power-on. Reaching the Power-on
Reset threshold voltage invokes the delay counter, which determines how long the device is kept in
RESET after V
below the detection level.
Symbol
Table
V
V
t
RST
POT
RST
BODLEVEL [2..0]
1. Values are guidelines only..
2. The Power-on Reset will not work unless the supply voltage has been below V
8-1. The POR is activated whenever V
Parameter
Power-on Reset Threshold Voltage
(rising)
Power-on Reset Threshold Voltage
(falling)
Minimum pulse width on RESET
Pin
RESET Pin Threshold Voltage
CC
Reset Logic
Reset Characteristics
rise. The RESET signal is activated again, without any delay, when V
(2)
Pull-up Resistor
Spike
Filter
RSTDIS
(1)
CKSEL[3:0]
Power-on Reset
Reset Circuit
SUT[1:0]
Brown-out
Watchdog
Oscillator
Generator
Circuit
Clock
CC
is below the detection level. The POR circuit can be
Condition
CK
Register (MCUSR)
MCU Status
DATA BUS
Delay Counters
0.2Vcc
Min.
Typ.
400
1.4
1.3
TIMEOUT
POT
(falling)
0.85Vcc
Max.
7734M–AVR–03/10
2.3
2.3
CC
decreases
Units
ns
V
V
V