Datasheet

65
11011B–ATARM–21-Feb-12
SAM3N
10.6.2.9 Interrupt (IRQ)
A interrupt, or IRQ, is an exception signalled by a peripheral, or generated by a software
request. All interrupts are asynchronous to instruction execution. In the system, peripherals use
interrupts to communicate with the processor.
For an asynchronous exception, other than reset, the processor can execute another instruction
between when the exception is triggered and when the processor enters the exception handler.
Privileged software can disable the exceptions that Table 10-9 on page 65 shows as having con-
figurable priority, see:
• “System Handler Control and State Register” on page 179
Table 10-9. Properties of the different exception types
Exception
number
(1)
1. To simplify the software layer, the CMSIS only uses IRQ numbers and therefore uses negative
values for exceptions other than interrupts. The IPSR returns the Exception number, see
“Interrupt Program Status Register” on page 48.
IRQ
number
(
1)
Exception
type Priority
Vector address
or offset
(2)
2. See “Vector table” on page 67 for more information.
Activation
1 - Reset
-3, the
highest
0x00000004 Asynchronous
2 -14 NMI -2 0x00000008 Asynchronous
3 -13 Hard fault -1 0x0000000C -
4 -12
Memory
management
fault
Configurable
(3)
3. See “System Handler Priority Registers” on page 176.
0x00000010 Synchronous
5-11Bus fault
Configurable
(3)
0x00000014
Synchronous when
precise,
asynchronous when
imprecise
6 -10 Usage fault
Configurable
(3)
0x00000018 Synchronous
7-10 - - - Reserved -
11 -5 SVCall
Configurable
(3)
0x0000002C Synchronous
12-13 - - - Reserved -
14 -2 PendSV
Configurable
(3)
0x00000038 Asynchronous
15 -1 SysTick
Configurable
(3)
0x0000003C Asynchronous
16 and
above
0 and
above
(4)
4. See the “Peripheral Identifiers” section of the datasheet.
Interrupt (IRQ)
Configurable
(5)
5. See “Interrupt Priority Registers” on page 158.
0x00000040 and
above
(6)
6. Increasing in steps of 4.
Asynchronous