Sharp MZ-5500 Tehnical Manual

~
ii) Interrupt proeessing
If the CPU is the Z-80A, the Z- 80A CTC a~tomatieal1y exeeutes the interrupt
aeknowledge eyele and the interrupt
/
the ease of the MZ - 5600, there is a
return cycle by its hardware. But,
need of exeeuting the interrupt ,
in
processing routine by the software. Besides, as the 8259A manages the
intcrrupt of the MZ-5500/5600, the interrupt terminate command (EOI) must
be issued to the 8259A, when it is possible to accept an interrupt of a
higher priority at the end ' of the interrupt processing routine. The
following deseribes the operational flow.
~
....
Interrupt proce66
-'
I
"OV DX,240H
IN , Al, DX
~ Dummy, interrupt acknowledge eyele
f
Interrupt cl,(\nnel
diS t i (\ ct,i on
I
"OV
"OV
OUT
MOV
OUT
DX.260H
Al,OEOH
DX, AL
Al,4 DH
DX.AL
~ Dummy, interrupt return cycle
.\
I
Jnterrupt
process
I
,
"OV Al,20H
~ EOI command
OUT 30H,AL
I
STJ
j
I
,
-....,
I RET
'-
1ii) Cheeking interrupt ehannel (MZ-5600 only)
The Z-80A CTC ~end~ out the interrupt vector in the
interrupt acknowledge eycle. Since the vector is
set in the AL register when th~ MZ-5600 executes
the dummy interrupt aeknowledge eyele, the channel
ean be known from the state of the register.
Because the vector "OH" has been set in the CTC-l,
the veetor "08H" must be set in the CTC-2.
Ch
3
Vector
06H
4 08H
5
OAH
6 ' OCH ,
I
7 OEH
l
35

Sharp MZ-5500 Specifications

General

Brand	Sharp
Model	MZ-5500
Category	Desktop
Language	English