INSTRUCTION SET
S3C8248/C8245/P8245/C8247/C8249/P8249
6-86
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:
EI
WFI
(Next instruction)
Main program
.
.
.
.
.
.
Interrupt occurs
Interrupt service routine
.
.
.
Clear interrupt flag
IRET
Service routine completed
(Enable global interrupt)
(Wait for interrupt)
Summary of Contents for S3C8248
Page 31: ...ADDRESS SPACES S3C8248 C8245 P8245 C8247 C8249 P8249 2 20 NOTES ...
Page 107: ...INTERRUPT STRUCTURE S3C8248 C8245 P8245 C8247 C8249 P8249 5 18 NOTES ...
Page 195: ...INSTRUCTION SET S3C8248 C8245 P8245 C8247 C8249 P8249 6 88 NOTES ...
Page 221: ...I O PORTS S3C8248 C8245 P8245 C8247 C8249 P8249 9 16 NOTES ...
Page 245: ...16 BIT TIMER 0 1 S3C8248 C8245 P8245 C8247 C8249 P8249 12 10 NOTES ...
Page 249: ...WATCH TIMER S3C8248 C8245 P8245 C8247 C8249 P8249 13 4 NOTES ...
Page 267: ...A D CONVERTER S3C8248 C8245 P8245 C8247 C8249 P8249 15 6 NOTES ...
Page 299: ...S3P8245 P8249 OTP S3C8248 C8245 P8245 C8247 C8249 P8249 21 8 NOTES ...
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