Samsung S3F80JB manual WFI Wait For Interrupt, Wfi, Opc 4n 3F

Models: S3F80JB

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INSTRUCTION SET

S3F80JB

 

 

WFI — Wait For Interrupt

WFI

Operation:

The CPU is effectively halted until an interrupt occurs, except that DMA transfers can still take place during this wait state. The WFI status can be released by an internal interrupt, including a fast interrupt .

Flags: No flags are affected.

Format:

Bytes Cycles Opcode (Hex)

opc

1 4n 3F

( n = 1, 2, 3, … )

Example: The following sample program structure shows the sequence of operations that follow a "WFI" statement:

Main program

.

.

.

EI

(Enable global interrupt)

WFI

(Wait for interrupt)

(Next instruction)

 

.

 

.

 

.

 

Interrupt occurs

Interrupt service routine

.

.

.

Clear interrupt flag

IRET

Service routine completed

6-86

Page 214
Image 214
Samsung S3F80JB manual WFI Wait For Interrupt, Wfi, Opc 4n 3F