Datasheet

UM10398 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
User manual Rev. 12.3 — 10 June 2014 466 of 547
NXP Semiconductors
UM10398
Chapter 28: LPC111x/LPC11Cxx Appendix: ARM Cortex-M0 reference
An interrupt request from a peripheral or from software can change the state of the
corresponding interrupt to pending.
Active — An exception that is being serviced by the processor but has not completed.
An exception handler can interrupt the execution of another exception handler. In this
case both exceptions are in the active state.
Active and pending — The exception is being serviced by the processor and there is a
pending exception from the same source.
28.4.3.2 Exception types
The exception types are:
Remark: See Section 28.1
for implementation of the NMI for specific parts.
Reset — Reset is invoked on power up or a warm reset. The exception model treats reset
as a special form of exception. When reset is asserted, the operation of the processor
stops, potentially at any point in an instruction. When reset is deasserted, execution
restarts from the address provided by the reset entry in the vector table. Execution restarts
in Thread mode.
NMI — A NonMaskable Interrupt (NMI) can be signalled by a peripheral or triggered by
software. This is the highest priority exception other than reset. It is permanently enabled
and has a fixed priority of 2. NMIs cannot be:
• masked or prevented from activation by any other exception
• preempted by any exception other than Reset.
HardFault — A HardFault is an exception that occurs because of an error during normal
or exception processing. HardFaults have a fixed priority of -1, meaning they have higher
priority than any exception with configurable priority.
SVCall — A supervisor call (SVC) is an exception that is triggered by the
SVC instruction.
In an OS environment, applications can use
SVC instructions to access OS kernel
functions and device drivers.
PendSV — PendSV is an interrupt-driven request for system-level service. In an OS
environment, use PendSV for context switching when no other exception is active.
SysTick — A SysTick exception is an exception the system timer generates when it
reaches zero. Software can also generate a SysTick exception. In an OS environment, the
processor can use this exception as system tick.
Interrupt (IRQ) — An 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.
Table 428. Properties of different exception types
Exception
number
[1]
IRQ
number
[1]
Exception
type
Priority Vector
address
[2]
1 - Reset -3, the highest 0x00000004
2-14NMI-2 0x00000008
3 -13 HardFault -1 0x0000000C
4-10 - Reserved - -
11 -5 SVCall Configurable
[3]
0x0000002C