OM13008,598 NXP Semiconductors, OM13008,598 Datasheet - Page 369

• Manufacturer Part Number: OM13008,598
• Description: BOARD LPC XPRESSO LPC122X
• Manufacturer: NXP Semiconductors
• Series: LPCXpressor

Specifications of OM13008,598

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 568-6642; OM13008

NXP Semiconductors
UM10441
User manual
25.3.3.2 Exception types
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.
The exception types are:
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:
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 361. Properties of different exception types
Exception
number
1
2
3
4-10
11
12-13
•
•
masked or prevented from activation by any other exception
preempted by any exception other than Reset.
[1]
All information provided in this document is subject to legal disclaimers.
IRQ
number
-
-14
-13
-
-5
-
Rev. 1.1 — 10 March 2011
[1]
Exception
type
Reset
NMI
HardFault
Reserved
SVCall
Reserved
Chapter 25: LPC122x Appendix ARM Cortex-M0
Priority
-3, the highest
-2
-1
-
Configurable
-
[3]
UM10441
© NXP B.V. 2011. All rights reserved.
-
Vector
address
0x00000004
0x00000008
0x0000000C
-
0x0000002C
[2]
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