ATTINY12-8SU Atmel, ATTINY12-8SU Datasheet - Page 28

• Manufacturer Part Number: ATTINY12-8SU
• Description: Microcontrollers (MCU) AVR 1K FLASH 64B EE 5V 8MHZ
• Manufacturer: Atmel

Specifications of ATTINY12-8SU

• Processor Series: ATTINY1x
• Core: AVR8
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 1 KB
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 6
• Number Of Timers: 1
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500
• Minimum Operating Temperature: - 40 C
• Cpu Family: ATtiny
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 8MHz
• Interface Type: SPI
• # I/os (max): 6
• Number Of Timers - General Purpose: 1
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC EIAJ
• Lead Free Status / Rohs Status: Details

Watchdog Reset
Register Description
MCU Status Register –
MCUSR of the ATtiny11
28
ATtiny11/12
When the Watchdog times out, it will generate a short reset pulse of 1 CK cycle dura-
tion. On the falling edge of this pulse, the delay timer starts counting the Time-out period
(t
Figure 21. Watchdog Reset during Operation
The MCU Status Register provides information on which reset source caused an MCU
reset.
• Bit 7..2 - Res: Reserved Bits
These bits are reserved bits in the ATtiny11 and always read as zero.
• Bit 1 - EXTRF: EXTernal Reset Flag
After a power-on reset, this bit is undefined (X). It will be set by an external reset. A
watchdog reset will leave this bit unchanged.
• Bit 0 - PORF: Power-on Reset Flag
This bit is set by a power-on reset. A watchdog reset or an external reset will leave this
bit unchanged.
To summarize, the following table shows the value of these two bits after the three
modes of reset.
Table 12. PORF and EXTRF Values after Reset
Bit
$34
Read/Write
Initial Value
TOUT
Reset Source
Power-on
External Reset
Watchdog Reset
). Refer to page 43 for details on operation of the Watchdog.
V
CC
R
7
0
-
R
6
0
-
R
5
0
-
CK
R
4
0
-
Unchanged
Undefined
EXTRF
1
R
3
0
-
2
R
0
-
EXTRF
See bit description
R/W
1
Unchanged
Unchanged
PORF
PORF
R/W
1
1006F–AVR–06/07
0
MCUSR