attiny25v ATMEL Corporation, attiny25v Datasheet - Page 52

• Manufacturer Part Number: attiny25v
• Description: Microcontroller With 2/4/8k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

9.2.2
9.3
9.3.1
52
Register Description
ATtiny25/45/85
Pin Change Interrupt Timing
MCUCR – MCU Control Register
An example of timing of a pin change interrupt is shown in
Figure 9-1.
The External Interrupt Control Register A 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 if the SREG I-flag and the corre-
sponding interrupt mask are set. The level and edges on the external INT0 pin that activate the
interrupt are defined in
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 interrupt. If low level interrupt is
pcint_setflag
Bit
0x35
Read/Write
Initial Value
pcint_in_(0)
PCINT(0)
pcint_syn
pin_sync
pin_lat
PCINT(0)
PCIF
clk
clk
Timing of pin change interrupts
7
BODS
R
0
LE
pin_lat
Table
6
PUD
R/W
0
D
Q
9-2. The value on the INT0 pin is sampled before detecting edges.
pin_sync
5
SE
R/W
0
PCINT(0) in PCMSK(x)
4
SM1
R/W
0
pcint_in_(0)
3
SM0
R/W
0
0
x
clk
Figure
2
BODSE
R
0
9-1.
pcint_syn
1
ISC01
R/W
0
0
ISC00
R/W
0
pcint_setflag
2586K–AVR–01/08
MCUCR
PCIF