Im n – Zilog EZ80F916 User Manual
Page 158
eZ80
®
CPU
User Manual
UM007715-0415
CPU Instruction Set
149
IM n
Set Interrupt Mode
Operation
Select the appropriate interrupt mode from Interrupt Mode 0, Interrupt Mode 1, and Inter-
rupt Mode 2.
Description
The n operand is any of the following interrupt modes:
•
Interrupt Mode 0—in this mode, the interrupting device inserts an instruction on the
data bus during an interrupt acknowledge cycle.
•
Interrupt Mode 1—in this mode, the CPU responds to an interrupt by executing a
restart to location
000038h
.
•
Interrupt Mode 2—in this mode, the interrupting device places the low-order address
of the interrupt vector on the data bus during an interrupt acknowledge cycle. The I
register provides the high-order byte of the interrupt vector table address. The 16-bit
value at the address {I, DATA[7:0]} is the starting address of the interrupt service rou-
tine.
Condition Bits Affected
None.
Attributes
Attributes
Not all eZ80
®
products support the three interrupt modes. Refer to the individual product
specification for information on supported interrupt modes.
Mnemonic
Operand
ADL Mode
Cycle
Opcode (hex)
IM
0
X
2
ED, 46
IM
1
X
2
ED, 56
IM
2
X
2
ED, 5E