Z86E3016PSG Datasheet, PDF (345/348 Pages) Zilog, Inc. – Z86E3016PSG

Z8 CPU
User Manual
327
Watch-Dog Timer Enable During Halt Mode
WDh
Instruction Format
OPC
Cycles
6
OPC
(Hex)
4F
Operation
When this instruction is executed it will enable the WDT (Watch–Dog
Timer) during HALT mode. If this instruction is not executed the WDT
will stop when entering HALT mode. This instruction does not clear the
counter, it just makes it possible to have the WDT function running during
HALT mode. A WDh instruction executed without executing WDT (5Fh)
has no effect.
Flag
Z
S
V
D
H
Description
Undefined
Undefined
Undefined
Unaffected
Unaffected
Note: The WDh instruction should not be used following any instruction in
which the condition of the flags is important.
Example
If the WDT is enabled, the statement:
WDh
Op Code: .BYTE 4Fh
will enable the WDT in HALT mode.
UM001602-0904
Instruction Description