atmega163l ATMEL Corporation, atmega163l Datasheet - Page 26

• Manufacturer Part Number: atmega163l
• Description: Atmega163 8-bit Avr Microcontroller With 16k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Power-on Reset
26
ATmega163(L)
Table 6. Number of Watchdog Oscillator Cycles
Note:
A Power-on Reset (POR) pulse is generated by an On-chip detection circuit. The detec-
tion level is defined in Table 4. The POR is activated whenever V
detection level. The POR circuit can be 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. Reach-
ing the Power-on Reset threshold voltage invokes a delay counter, which determines
the delay, for which the device is kept in RESET after V
the delay counter can be defined by the user through the CKSEL Fuses. The different
selections for the delay period are presented in Table 5. The RESET signal is activated
again, without any delay, when the V
Figure 25. MCU Start-up, RESET Tied to V
BODLEVEL
Unprogrammed
Unprogrammed
Unprogrammed
Unprogrammed
Programmed
Programmed
Programmed
Programmed
INTERNAL
TIME-OUT
RESET
RESET
VCC
1. The Bodlevel Fuse can be used to select start-up times even if the Brown-out Detec-
tion is disabled (BODEN Fuse unprogrammed).
V
V
POT
RST
V
CC
t
TOUT
Condition
2.7V
2.7V
2.7V
2.7V
4.0V
4.0V
4.0V
4.0V
CC
decreases below detection level.
CC
.
Time-out
(1)
130 µs
4.2 ms
5.8 ms
67 ms
92 ms
30 µs
10 µs
35 µs
CC
rise. The Time-out Period of
Number of Cycles
CC
16K
64K
1K
4K
32
32
8
8
1142E–AVR–02/03
is below the