attiny11 ATMEL Corporation, attiny11 Datasheet - Page 22

• Manufacturer Part Number: attiny11
• Description: 8-bit Microcontroller With 1k Byte Flash
• Manufacturer: ATMEL Corporation

System Control and
Reset
Reset Sources
22
ATtiny11/12
The ATtiny11/12 provides three or four sources of reset:
•
•
•
•
During reset, all I/O registers are then set to their initial values, and the program starts
execution from address $000. The instruction placed in address $000 must be an RJMP
– relative jump – instruction to the reset handling routine. If the program never enables
an interrupt source, the interrupt vectors are not used, and regular program code can be
placed at these locations. The circuit diagram in Figure 15 shows the reset logic for the
ATtiny11. Figure 16 shows the reset logic for the ATtiny12. Table 7 defines the electrical
parameters of the reset circuitry for ATtiny11. Table 9 shows the parameters of the reset
circuitry for ATtiny12.
Figure 15. Reset Logic for the ATtiny11
Table 7. Reset Characteristics for the ATtiny11
Note:
Symbol
V
V
RESET
POT
RST
VCC
Power-on Reset. The MCU is reset when the supply voltage is below the power-on
reset threshold (V
External Reset. The MCU is reset when a low level is present on the RESET pin for
more than 50 ns.
Watchdog Reset. The MCU is reset when the Watchdog timer period expires and
the Watchdog is enabled.
Brown-out Reset. The MCU is reset when the supply voltage V
certain voltage (ATtiny12 only).
(1)
1. The Power-on Reset will not work unless the supply voltage has been below V
(falling).
Parameter
Power-on Reset Threshold Voltage (rising)
Power-on Reset Threshold Voltage (falling)
RESET Pin Threshold Voltage
Power-on Reset
Reset Circuit
RC Oscillator
Watchdog
On-chip
Circuit
Timer
POT
).
Q3
POR
20-stage Ripple Counter
Q9
Q13
Q19
Min
1.0
0.4
0.6 V
Typ
1.4
0.6
CC
CC
falls below a
S
R
Max
1.8
0.8
1006F–AVR–06/07
Q
Q
Units
V
V
V
POT