Wfi — Wait For Interrupt - Samsung S3F84B8 User Manual

S3F84B8_UM_REV 1.00
6.3.72 WFI — WAIT FOR INTERRUPT
WFI
Operation:
The CPU is halted until an interrupt occurs; even though DMA transfers can still take place during
the wait state. The WFI status can be released by an internal interrupt, including a fast interrupt.
No flags are affected.
Flags:
Format:
opc
The following sample program structure shows the sequence of operations that follow a "WFI"
Example:
statement:
Main program
.
.
.
EI
WFI
(Next instruction)
.
.
.
Interrupt occurs
Interrupt service routine
.
.
.
Clear interrupt flag
IRET
Service routine completed
Bytes Cycles
1
( n = 1, 2, 3, ... )
(Enable global interrupt)
(Wait for interrupt)
6-84
6 INSTRUCTION SET
Opcode
(Hex)
4n 3F