Z8
®
CPU
User Manual
UM001604-0108
Interrupts
104
The proper sequence for programming the interrupt edge select bits is (assumes IPR and
IMR have been previously initialized).
IRQ Software Interrupt Generation
IRQ can be used to generate software interrupts by specifying IRQ as the destination of
any instruction referencing the Z8
®
Standard Register File. These Software Interrupts
(SWI) are controlled in the same manner as hardware generated requests (in other words,
the IPR and the IMR control the priority and enabling of each SWI level).
Table 21. IRQ Register Configuration*
IRQ
Interrupt Edge
D7
D6
P31
P32
0
0
F
F
0
1
F
R
1
0
R
F
1
1
R/F
R/F
*F = Falling Edge; R = Rising Edge.
DI
;Inhibit all interrupts until input edges are
configured.
OR
IRQ,#XX 000000b
;Configure interrupt; do not disturb edges
as required—IRQ 0-5.
EI
;Re-enable interrupts.
Figure 99. IRQ Reset Functional Logic Diagram
S
Interrupt Request Register
(IRQ, FAh)
RESET
El Instruction
POR
R
