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INTRODUCTION
The Z8
P
LUS
core allows 15 different interrupts from a variety of sources:
external inputs
on-chip peripherals
software
Interrupts can be masked by using the Interrupt Mask Register. All interrupts can be globally disabled by
setting the master Interrupt Enable, bit
7
in the Interrupt Mask Register, to 0, with a Disable Interrupt (
DI
)
instruction. Interrupts are globally enabled by setting bit
7
to
1
with an Enable Interrupt (
EI
) instruction.
There are four interrupt control registers: the Interrupt Request Registers
(IREQ
and
IREQ2
) and the Inter-
rupt Mask registers (
IMASK
and
IMASK2
). Figure 4-1 shows addresses and identifiers for the interrupt
control registers. Figure 4-2 is a block diagram showing the Interrupt Mask and Interrupt Priority logic.
Figure 4-1. Interrupt Control Register Addresses and Identifiers
Register
HEX
Interrupt Mask
Interrupt Request
Identifier
0FBH
0FAH
IMASK
IREQ
Interrupt Mask 2
Interrupt Request 2
0F9H
0F8H
IMASK2
IREQ2