ZiLOG Z8 User Manual page 171

ZiLOG
HALT
HALT
HALT
Halt
HALT
Instruction Format:
Operation:
The HALT instruction turns off the internal CPU clock, but not the XTAL oscillation. The counter/timers and the
external interrupts IRQ1, IRQ2, and IRQ3 remain active. The devices are recovered by interrupts, either externally
or internally generated.
Flags: C: Unaffected
Z: Unaffected
S: Unaffected
V: Unaffected
D: Unaffected
H: Unaffected
Note:
In order to enter HALT mode, it is necessary to first flush the instruction pipeline to avoid suspending execution in
mid-instruction. The user must execute a NOP immediately before the execution of the HALT instruction.
Example:
Assuming the Z8 is in normal operation, the statements:
place the Z8 into HALT mode.
UM001601-0803
NOP
HALT
Op Codes: FF 7F
Z8 Microcontrollers
Instruction Descriptions and Formats
12-31