Datasheet

187
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
12.6.11.11WFE
Wait For Event.
Syntax
WFE{cond}
where:
cond is an optional condition code, see “Conditional Execution” .
Operation
WFE is a hint instruction.
If the event register is 0, WFE suspends execution until one of the following events occurs:
 An exception, unless masked by the exception mask registers or the current priority level
 An exception enters the Pending state, if SEVONPEND in the System Control Register is set
 A Debug Entry request, if Debug is enabled
 An event signaled by a peripheral or another processor in a multiprocessor system using the SEV instruction.
If the event register is 1, WFE clears it to 0 and returns immediately.
For more information, see “Power Management” .
Condition Flags
This instruction does not change the flags.
Examples
WFE ; Wait for event
12.6.11.12WFI
Wait for Interrupt.
Syntax
WFI{cond}
where:
cond is an optional condition code, see “Conditional Execution” .
Operation
WFI is a hint instruction that suspends execution until one of the following events occurs:
 An exception
 A Debug Entry request, regardless of whether Debug is enabled.
Condition Flags
This instruction does not change the flags.
Examples
WFI ; Wait for interrupt
12.7 Cortex-M4 Core Peripherals
12.7.1 Peripherals
 Nested Vectored Interrupt Controller (NVIC)
The Nested Vectored Interrupt Controller (NVIC) is an embedded interrupt controller that supports low latency
interrupt processing. See Section 12.8 ”Nested Vectored Interrupt Controller (NVIC)”