ARM Cortex-M4 - Wfe

The Cortex-M4 Instruction Set
ARM DUI 0553A Copyright © 2010 ARM. All rights reserved. 3-168
ID121610 Non-Confidential
3.12.11 WFE
Wait For Event.
Syntax
WFE{cond}
where:
cond Is an optional condition code, see Conditional execution on page 3-18.
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 on page 2-32.
Condition flags
This instruction does not change the flags.
Examples
WFE ; Wait for event