ATTINY261-15MZ Atmel, ATTINY261-15MZ Datasheet - Page 52

• Manufacturer Part Number: ATTINY261-15MZ
• Description: MCU AVR 2K FLASH 15MHZ 32-QFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY261-15MZ

• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Speed: 16MHz
• Number Of I /o: 16
• Eeprom Size: 128 x 8
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Program Memory Size: 2KB (2K x 8)
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Connectivity: USI
• Core Size: 8-Bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

11. External Interrupts
11.1
11.1.1
52
Register Description
ATtiny261/ATtiny461/ATtiny861
MCUCR – MCU Control Register
The External Interrupts are triggered by the INT0 or INT1 pin or any of the PCINT15..0 pins.
Observe that, if enabled, the interrupts will trigger even if the INT0, INT1 or PCINT15..0 pins are
configured as outputs. This feature provides a way of generating a software interrupt. Pin
change interrupts PCI will trigger if any enabled PCINT15..0 pin toggles. The PCMSK Register
control which pins contribute to the pin change interrupts. Pin change interrupts on PCINT15..0
are detected asynchronously. This implies that these interrupts can be used for waking the part
also from sleep modes other than Idle mode.
The INT0 and INT1 interrupts can be triggered by a falling or rising edge or a low level. This is
set up as indicated in the specification for the MCU Control Register – MCUCR. When the INT0
interrupt is enabled and is configured as level triggered, the interrupt will trigger as long as the
pin is held low. Note that recognition of falling or rising edge interrupts on INT0 or INT1 requires
the presence of an I/O clock, described in
Low level interrupt on INT0 is detected asynchronously. This implies that this interrupt can be
used for waking the part also from sleep modes other than Idle mode. The I/O clock is halted in
all sleep modes except Idle mode.
Note that if a level triggered interrupt is used for wake-up from Power-down, the required level
must be held long enough for the MCU to complete the wake-up to trigger the level interrupt. If
the level disappears before the end of the Start-up Time, the MCU will still wake up, but no inter-
rupt will be generated. The start-up time is defined by the SUT and CKSEL Fuses as described
in
The MCU Register contains control bits for interrupt sense control.
• Bits 1, 0 – ISC01, ISC00: Interrupt Sense Control 0 Bit 1 and Bit 0
The External Interrupt 0 is activated by the external pin INT0 or INT1 if the SREG I-flag and the
corresponding interrupt mask are set. The level and edges on the external INT0 or INT1 pin that
activate the interrupt are defined in
before detecting edges. If edge or toggle interrupt is selected, pulses that last longer than one
clock period will generate an interrupt. Shorter pulses are not guaranteed to generate an inter-
rupt. If low level interrupt is selected, the low level must be held until the completion of the
currently executing instruction to generate an interrupt.
Table 11-1.
Bit
0x35 (0x55)
Read/Write
Initial Value
“System Clock and Clock Options” on page
ISC01
0
0
1
1
Interrupt 0 Sense Control
7
–
R
0
ISC00
0
1
0
1
6
PUD
R/W
0
Description
The low level of INT0 or INT1 generates an interrupt request.
Any logical change on INT0 or INT1 generates an interrupt request.
The falling edge of INT0 or INT1 generates an interrupt request.
The rising edge of INT0 or INT1 generates an interrupt request.
5
SE
R/W
0
Table
4
SM1
R/W
0
11-1. The value on the INT0 or INT1 pin is sampled
“Clock Systems and their Distribution” on page
25.
3
SM0
R/W
0
2
–
R
0
1
ISC01
R/W
0
0
ISC00
R/W
0
7753F–AVR–01/11
MCUCR
25.