Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet

SAM4S Series [DATASHEET]

Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14

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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.

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.

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.

Notes: 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 

.

2. See 

 for more information

3. See 

4. See 

5. Increasing in steps of 4.

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 

 shows as having configurable priority, see:





. 

For more information about hard faults, memory management faults, bus faults, and usage faults, see 

1

–

Reset

-3, the highest

0x00000004

Asynchronous

2

-14

NMI

-2

0x00000008

Asynchronous

3

-13

Hard fault

-1

0x0000000C

–

4 -1

2

Memory

management fault

Configurable

0x00000010

Synchronous

5

-11

Bus fault 

Configurable

0x00000014

Synchronous when precise, 

asynchronous when imprecise

6

-10

Usage fault 

Configurable

0x00000018

Synchronous

7–10

–

–

–

Reserved

–

11

-5

SVCall

Configurable

0x0000002C

Synchronous

12–13

–

–

–

Reserved

–

14

-2

PendSV

Configurable

0x00000038

Asynchronous

15

-1

SysTick

Configurable

0x0000003C Asynchron

ous

16 and above

0 and above

Interrupt (IRQ)

Configurable

0x00000040 and above

Asynchronous