at32uc3b0512-z2ues ATMEL Corporation, at32uc3b0512-z2ues Datasheet - Page 101

• Manufacturer Part Number: at32uc3b0512-z2ues
• Description: 32-bit Avr Microcontroller
• Manufacturer: ATMEL Corporation

13.6.2
Figure 13-2. Timing Diagram, Synchronous Interrupts, High Level or Rising Edge
32059J–12/2010
EXTINTn/NMI
FILTER off
FILTER on
ISR.INTn:
ISR.INTn:
CLK_SYNC
Synchronization and Filtering of External Interrupts
one is written to the corresponding bit in the Interrupt Clear Register (ICR) or the interrupt is
disabled.
Writing a one to the INTn bit in the Enable Register (EN) enables the external interrupt on pin
EXTINTn, while writing a one to INTn bit in the Disable Register (DIS) disables the external inter-
rupt. The Control Register (CTRL) can be read to check which interrupts are enabled. If a bit in
the CTRL register is set, but the corresponding bit in IMR is not set, an interrupt will not propa-
gate to the interrupt controller. However, the corresponding bit in ISR will be set, and
EIC_WAKE will be set.
If the CTRL.INTn bit is zero, then the corresponding bit in ISR will always be zero. Disabling an
external interrupt by writing to the DIS.INTn bit will clear the corresponding bit in ISR.
In synchronous mode the pin value of the EXTINTn pin is synchronized to CLK_SYNC, so
spikes shorter than one CLK_SYNC cycle are not guaranteed to produce an interrupt. The syn-
chronization of the EXTINTn to CLK_SYNC will delay the propagation of the interrupt to the
interrupt controller by two cycles of CLK_SYNC, see
on page 102
It is also possible to apply a filter on EXTINTn by writing a one to INTn bit in the FILTER register.
This filter is a majority voter, if the condition for an interrupt is true for more than one of the latest
three cycles of CLK_SYNC the interrupt will be set. This will additionally delay the propagation of
the interrupt to the interrupt controller by one or two cycles of CLK_SYNC, see
page 101
and
for examples (FILTER off).
Figure 13-3 on page 102
for examples (FILTER on).
Figure 13-2 on page 101
AT32UC3B
and
Figure 13-2 on
Figure 13-3
101